The research about Near Earth Objects (NEOs) is a major topic in planetary science. One reason is the potential hazard some of them pose to human beings and, more in general, to life on our planet. Moreover, the physical characterization of NEOs allows us to put constraints on the material accreted in the protoplanetary nebula at different solar distances and can give us insights into the early processes that governed the formation and the evolution of planets - including the delivery of water and organics to Earth -, and into further evolutionary processes that acted on asteroid since their formation - such as collisions and non-gravitational effects.The "NEOROCKS - The NEO Rapid Observation, Characterization and Key Simulations" Collaborative Research Project has been recently approved to address the topic c) "Improvement of our knowledge of the physical characteristics of the NEO population" of the call SU-SPACE-23-SEC-2019 from the Horizon 2020 - Work Programme 2018-2020 Leadership in Enabling and Industrial Technologies - Space.The aims of NEOROCKS are:to develop and validate advanced mathematical methods and innovative algorithms for NEO orbit determination and impact monitoring; to organize follow-up astronomical observations of NEOs efficiently, in order to obtain high-quality data needed to derive their physical properties, giving priority to timely addressing potentially hazardous objects; to improve dramatically statistical analysis, modelling and computer simulations aimed to understand the physical nature of NEOs, focussing on small size objects, which are of uttermost importance for designing effective impact mitigation measures in space and on the ground; to ensure maximum visibility and dissemination of the data beyond the timeline of the project, by hosting it in an existing astronomical data center facility; to foster European and international cooperation on NEO physical characterization, providing scenarios and roadmaps with the potential to scale-up at a global level the experience gained during the project; to apply and guarantee continuity of educational and public outreach activities needed to improve significantly public understanding and perception of the asteroid hazard, counteracting the spreading of "fake news" and unjustified alarms. Acknowledgement: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 870403 (project NEOROCKS).

The ESA Hera mission will contribute to the first deflection test of an asteroid with the NASA DART mission and provide unique information on asteroid science.

We present our results about the detection of new asteroids by Gaia. Since the end of 2016, an alerting system is operating and it reacts when unknown and moving objects are detected by the probe. In spite of the short length of the orbital arcs observed by transits in the Gaia focal plane, it is possible to calculate preliminary orbital beams and to determine search areas for a ground-based observatory. On the basis of these data, the Gaia-FUN-SSO network of observatories, set up for this task, is able to validate the detections and to consolidate the asteroid orbits.

We present here the first integration of the search mechanism for solar system objects through ESASky. Based on the IMCCE Eproc software for ephemeris pre-computation, it allows fast discovery of photometry observations from ESA astronomical missions that potentially contain these objects within their field of view. In this first integration, the user can input a target name and retrieve on-the-fly the results for all the observations that match the input provided, that is, that contains within the exposure time frame the ephemerides of such objects. At the moment the search mechanism provides access to three major ESA missions, XMM-Newton, Hubble Space Telescope and Herschel Space Observatory, to be extended at a later stage to other relevant data assets.

In Astronomy, there is a tendency to build machine learning codes for very specific object detection in images. The classification of asteroids and non-asteroids should be no different than the classification of asteroids, stars, galaxies, cosmic rays, ghosts or any other artefact found in astronomical data. In computer science, it is not uncommon for machine learning to train on hundreds of thousands of object categories, so why are we not there yet? I will talk about image classification with deep learning and how we can make use of existing tools such as the ESA science archive, ESAsky and citizen science to help realise the full potential of object detection and image classification in Astronomy.

Here, we will present an overview of the results obtained after 2.5 years of observations with VLT/SPHERE.

According to the size-frequency distribution (SFD) of the Main Belt, there are approximately 4 times 10⁵ small (D=2-3 km) projectiles which determine the surface topography of large (D>100 km) targets. Nowadays, the topography is accessible to adaptive-optics observations by the VLT/SPHERE/ZIMPOL instrument, which typically have a pixel scale 3 km and capability to resolve Dc = 30-40 km craters in suitably illuminated areas. We used statistical collisional models (Monte-Carlo) to compute intrinsic collisional probabilities, impact velocities, expected number of catastrophic collisions, numbers of cratering events, taking into account not only mean numbers but also their dispersion. Even within the Main Belt, collisional environment can be very different from target to target.

We present the utilisation of genetic algorithm to create asteroid models from lightcurves and VLT/SPHERE adaptive-optics images. The lightcurve-only non-convex SAGE method was extended to include disk-resolved data during the modelling, alongside lightcurves.

Gaia, the billion of stars surveyor, also regularly observe small bodies from our Solar System. Among those, some are not known at the time of their observation by Gaia. Within the Data Processing and Analysis Consortium, a daily processing as been set in place to release information on when, where, and how to observe these potential discoveries by Gaia: https://gaiafunsso.imcce.fr/. We will report on the activity of the network of observers, that led to over 120 candidates confirmed from the ground, and three likely discoveries.

The second Gaia data release contains for the first time 2 millions of observations for more than 14000 minor bodies of our solar system. The accuracy of these observations is without precedents and it opens a completely new perspective on asteroid studies. We present our direct detections of the Yarkovsky effect, which is the most important non-gravitational perturbations changing the orbits of small asteroids over long time span, using Gaia DR2 observations. This secular effect can be detected from astrometry, but we had to developed new methods to combine the amazing accuracy of Gaia observations with tens of years of available ground-based ones. We also use these detections to constraint the values of the asteroid density, which are usually not measured on small bodies.

We applied the ADAM inversion algorithm to the combined optical and VLT/Sphere disk-resolved data and obtained a detailed 3D shape model with local topography of asteroid (7) Interamnia, the sixth largest body in the main belt. Moreover, we also estimated the size and bulk density of Interamnia. The resulting shape model is rather round and lacking any large scale concavities or even topographic features such as impact craters although we should be able to resolve those as large as ?40 km.

We present high-angular resolution images of the triple asteroid system (87) Sylvia, Romulus, and Remus obtained with the SPHERE/ZIMPOL instrument at the ESO VLT. The images, combined with historical optical lightcurves allows to reconstruct the 3-D shape of Sylvia. The precise astrometry of the two satellites in the SPHERE/ZIMPOL images, combined with tens of measurements performed on archival VLT/NACO, Keck/NIRC2, Gemini/NIRI images allows to determine minute orbital elements for the two satellites and to constraint the mass of Sylvia. From our measurement, we determine the density of Sylvia. We will discuss the topography of Sylvia, the dynamical properties of the system, and the implications of its density.

The ESA Euclid mission has been designed to map the geometry of the dark Universe. Scheduled for launch in 2022, it will conduct a visible and near-infrared imaging survey over a third of the sky, four magnitude deeper than Gaia. Although the survey will avoid the ecliptic, the survey pattern in repeated sequences of four broad-band filters seems well-adapted to Solar System objects detection and characterization. I will present the expected the impact of Euclid on planetary sciences and the current status of the Solar System Science Working Group (SSO SWG) of the Euclid consortium.

Pallas is the largest object in the inner Solar System never explored by spacecraft. We will present high angular resolution images of this object acquired from the ground with the SPHERE camera on the Very Large Telescope. Using our observations, we will present new constraints on the formation and subsequent thermal and collisional evolution of Pallas.

Discovery and identification of Solar System Objects (SSOs) are necessary preceding steps to their characterization. We present here the results obtained after searching the HST archive for near-Earth objects (NEOs). Cross-matching the orbits of all 19,000 NEOs in the ASTORB Database with the footprints of 1.3 million HST exposures using an algorithm developed by the IMCCE and the ESASky team, we identified 8,666 potential serendipitous observations of NEOs with ephemeris uncertainties equal to or below 1 degree. Visual inspection of 317 images revealed 15 observations of 10 unique NEOs, of which we extracted the astrometry and photometry. More objects may be present in the images but large ephemeris uncertainties and degrees of image contamination hinder the identification. Our application highlights the potential of this method and harvesting the HST archive for SSO detections, as well as the need of astrometric measurements to refine the orbital calculations. Furthermore, we searched for SSOs in public image repositories using a versatile detection pipeline we developed. The pipeline is able to identify both known and unknown SSOs in astronomical images mainly based on their apparent motion, which naturally favours the detection of the fast moving NEOs. We present the results obtained and difficulties encountered using GTC/OSIRIS (DR1) and OAJ/T80Cam (DR1), including the detection of about 4,800 SSOs. Using the IMCCE SkyBoT service to cross-match the SSO detections, we identified about 4,000 of these objects, from close NEOs to distant objects of the Kuiper Belt. We will further describe the on-going work done with ESO/VISTA, ESO/VST, UKIRT/WFCAM, and Subaru/HSC images. Identifying the vast amount of NEOs and other exciting objects hidden in these archives can greatly decrease their ephemeris uncertainties and add valuable photometric measurements for spectral classification, a fundamental tasks in their characterization.

We provide a summary of achievements of the VESPA activity in current Europlanet-2020 program, and prospects for a follow-up.

Small Solar System bodies are objects that are neither planets nor dwarf planets, nor satellites of a planet or dwarf planet. More than 750,000 small Solar System bodies are known today, most of them asteroids, occupying a variety of orbits ranging from near-Earth to the Kuiper belt. Their study is motivated by their intrinsic importance as remnants of the early stages of the solar system formation process as well as by practical reasons concerning space exploration or the impact frequency with Earth. We describe here a methodology to identify asteroids serendipitously observed in the WFCAM Transit Survey using Virtual Observatory tools like SkyBoT, Miriade, TOPCAT, STILTS and Aladin. We provide near 15,000 accurate positions and J-band magnitudes for over 1,600 asteroids. We build light curves and plan to use them to determine their fundamental physical parameters, such as the asteroid's shape, rotational period or the binary nature.

VESPA is an extension of the Virtual Observatory to handle planetary science data. This is a contributive system where data services can be provided by the community.

We describe here a citizen-science project conducted by the Spanish Virtual Observatory to improve the orbits of near-Earth asteroids (NEAs) and Mars crossers (MCs) using data from astronomical archives. At the time of writing, almost 4000 registered users from 76 different countries have made more than 420 000 measurements which have improved the orbital elements of 613 NEAs and 508 MCs (3% and 4% of the total number of these types of asteroids, respectively). Even more remarkable is the fact that these results have been obtained at zero cost of telescope time as asteroids were serendipitously observed while the surveys were being carried out. This demonstrates the enormous scientific potential hidden in astronomical archives and the power of Virtual Observatory tools to mine them. The excellent reception of the project as well as the results obtained makes it a valuable initiative to improve the knowledge of near-Earth asteroids and Mars crossers.

Hera provides a robust and cost-effective means to perform a planetary defense validation test with a solid balance between risk and innovation. In the frame of the AIDA collaboration, Hera contributes to a truly international planetary defense initiative. It will bring completely new knowledge and insights on asteroid science that will be of great benefit to those seeking a deeper understanding of the processes underlying solar system formation.

Progress report from VESPA activity in Europlanet2020 programme.

We describe here a methodology to identify asteroids serendipitously observed in large-area astronomical surveys using Virtual Observatory tools such as SkyBoT, TOPCAT, and STILTS. The application of this method on the WFCAM Transit Survey is demonstrated. We provide almost 15,000 accurate positions (mean RMS 0.15 arcsec) and J-band magnitudes (typical accuracy of 0.11 mag) for over 1600 asteroids. From the repeated observations we build light curves and use them to determine the asteroid fundamental physical parameters, such as their rotational period or their multiplicity.

The Europlanet2020 program, started Sept 1st, 2015 for 4 years, includes an activity adapting Virtual Observatory (VO) techniques to handle Planetary Science data. The objective of this activity, VESPA, is to facilitate searches in big archives as well as sparse databases, to provide simple data access and on-line visualization, and to allow small data providers to make their data available in an interoperable environment with minimum effort. This system makes intensive use of studies and developments led in Astronomy (IVOA), solar Physics (HELIO), and space archive services (IPDA). The VESPA data access system, based on a prototype developed in a previous EU program, has been hugely improved during the first two years of Europlanet2020 [1]: the infrastructure has been upgraded to describe data in many fields more accurately (Data Model and EPN-TAP access protocol); the main user search interface (http://vespa.obspm.fr) has been redesigned to provide more flexibility; alternative ways to access Planetary Science data services from VO tools have been implemented (in TOPCAT, Aladin, CASSIS, 3Dview, etc) in addition to receiving data from the main interface; connection with VO tools are being improved to handle specificities of Solar System data, e.g., measurements in reflected light, coordinate systems, etc; current steps include the development of a connection between the VO world and GIS tools, and integration of Heliophysics, planetary plasma, and mineral spectroscopy data to support of the analysis of observations. Besides, existing data services have been updated, and new services have been designed and installed. The global objective is already overstepped, with 37 services open and about 15 more being finalized. A procedure has been identified to install data services with little resources, and hands-on sessions are organized twice a year at EGU and EPSC conferences in Europe; this is expected to favour the installation of services by individual research teams, e.g. to distribute derived data related to a published study. In complement, regular discussions are held with big data providers, starting with space agencies (IPDA). Common projects with ESA and NASA's PDS have been started, with the goal to connect PDS4 and EPN-TAP. In parallel, a Solar System Interest Group has been started at the IVOA, where several VESPA partners contribute; the goal here is to adapt existing astronomy standards to Planetary Science. The Europlanet 2020 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208. [1] Erard et al 2018, Planet. Space Sci.150, 65-85. 10.1016/j.pss.2017.05.013. ArXiv 1705.09727

Knowing the asteroid belt is the key to provide a reliable history ofour solar system. The main question which has been raised in the lastyears is: given our available data, does our classification ofasteroid into families provide a reliable history of the collisionalevolution of our solar system?We have done huge steps forward, but the real revolution isrepresented by the ESA Gaia mission. Starting from April 2018, Gaiawill provide observations of solar system objects with sub-mas accuracy,completely changing our vision of the asteroid belt.We present an overview of the main results achieved by the second Gaiadata release, focusing our attention especially on cratering families,which are the results of past collisions between asteroids that haveproduced many small fragments from a large parent body.We present our classification of cratering families, including theirage determination computed mixing dynamical and physical propertiesthat the asteroids share in the same family.

The Europlanet H2020 program started on 1/9/2015 for 4 years. It includes an activity to adapt Virtual Observatory (VO) techniques to Planetary Science data called VESPA. The objective is to facilitate searches in big archives as well as sparse databases, to provide simple data access and on-line visualization, and to allow small data providers to make their data available in an interoperable environment with minimum effort.The VESPA system, based on a prototype developed in a previous program [1], has been hugely improved during the first two years of Europlanet H2020: the infrastructure has been upgraded to describe data in many fields more accurately; the main user search interface (http://vespa.obspm.fr) has been redesigned to provide more flexibility; alternative ways to access Planetary Science data services from VO tools have been implemented; VO tools are being improved to handle specificities of Solar System data, e.g. measurements in reflected light, coordinate systems, etc. Current steps include the development of a connection between the VO world and GIS tools, and integration of Heliophysics, planetary plasmas, and mineral spectroscopy data to support of the analysis of observations.Existing data services have been updated, and new ones have been designed. The global objective is already overstepped, with 34 services open and 20 more being finalized.A procedure to install data services has been documented, and hands-on sessions are organized twice a year at EGU and EPSC; this is intended to favour the installation of services by individual research teams, e.g. to distribute derived data related to a published study. In complement, regular discussions are held with big data providers, starting with space agencies (IPDA). Common projects with ESA and NASA's PDS have been engaged, with the goal to connect PDS4 and EPN-TAP. In parallel, a Solar System Interest Group has just been started in IVOA; the goal is here to adapt existing astronomy standards to Planetary Science.The Europlanet 2020 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.[1] Erard et al 2014, Astronomy & Computing 7-8, 71-80. http://arxiv.org/abs/1407.4886

The binary near-Earth asteroid (65803) Didymos is the target for the two components of the Asteroid Impact and Deflection Assessment (AIDA) mission. The NASA DART (Double Asteroid Redirection Test) mission is scheduled to impact the Didymos secondary during its apparition in 2022. ESA's proposed Hera mission will arrive years later to obtain in situ observations of the system following the DART impact. One key scientific goal of AIDA is to measure and characterize the deflection caused by the impact. A combination of spacecraft and ground and space based optical and radar observations in 2022 will provide the required data for AIDA to meet its top-level mission goals. Photometric observations of Didymos were taken in 2003, 2015, and 2017. These observations have been used to determine the orbital period and constrain the orbital pole of the system. We used these observations to determine the number and precision of observations needed prior to the DART impact in 2022. We will observe the Didymos system during the 2019 and 2020-2021 apparitions to further characterize the system by obtaining additional lightcurve observations and spectra. These planned observations will provide us with the opportunity to establish the state of the system before impact to a high level of precision. We will place additional constraints on the inclination of the satellite orbit, the long-term effects of Binary YORP (BYORP), and whether the satellite is in synchronous rotation with the primary. The Didymos apparitions in 2019 and 2020-2021 will be much fainter than that in 2022. We anticipate observations at a range of large ground-based and space-based facilities. We will discuss what is currently known about the Didymos system, our observing plans prior to the DART impact, and our observing plans during the impact apparition.

The Europlanet H2020 program started on 1/9/2015 for 4 years. It includes an activity to adapt Virtual Observatory (VO) techniques to Planetary Science data called VESPA. The objective is to facilitate searches in big archives as well as sparse databases, to provide simple data access and on-line visualization, and to allow small data providers to make their data available in an interoperable environment with minimum effort. The VESPA system has been hugely improved during the first three years of Europlanet H2020: the infrastructure has been upgraded to describe data in many fields more accurately; the main user search interface (http://vespa.obspm.fr) has been redesigned to provide more flexibility; alternative ways to access Planetary Science data services from VO tools have been implemented; VO tools are being improved to handle specificities of Solar System data, e.g. measurements in reflected light, coordinate systems, etc. Current steps include the development of a connection between the VO world and GIS tools, and integration of Heliophysics, planetary plasmas, and mineral spectroscopy data to support of the analysis of observations. Existing data services have been updated, and new ones have been designed. The global objective is already overstepped, with 42 services open (including ESA's PSA) and 15 more being finalized. A procedure to install data services has been documented, and hands-on sessions are organized twice a year at EGU and EPSC; this is intended to favour the installation of services by individual research teams, e.g. to distribute derived data related to a published study. In complement, regular discussions are held with big data providers, starting with space agencies (IPDA). Common projects with PDS have been engaged, with the goal to connect PDS4 and EPN-TAP based on a local data dictionary. In parallel, a Solar System Interest Group has been established in IVOA; the goal is here to adapt existing astronomy standards to Planetary Science. The Europlanet 2020 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208. [1] Erard et al 2014, Astronomy & Computing 7-8, 71-80. http://arxiv.org/abs/1407.4886

The vast majority of the geological constraints (i.e., internal structure via the density, cratering history) for main belt asteroids have so far been obtained via dedicated interplanetary missions (e.g., Rosetta, DAWN). The high angular resolution of SPHERE/ZIMPOL (one pixel represents 3.6 x 3.6 mas on sky), the new-generation visible adaptive-optics camera at ESO/VLT, implies that such science objective can now be investigated from the ground for a large fraction of D?100 km main-belt asteroids (most of these bodies possess an angular diameter around opposition larger than 100 mas). The sharp images acquired by this instrument can be used to constrain accurately the shape and thus volume of these bodies (hence density when combined with mass estimates) and to characterize the distribution and topography of D?30 km craters across their surfaces. To make substantial progress in our understanding of the shape, internal compositional structure (i.e., density) and surface topography of large main belt asteroids, we are carrying out an imaging survey via an ESO Large program entirely performed in service mode with seeing constraints <0.8" (152h in total; PI: P. Vernazza; ID: 199.C-0074; the observations are spread over 4 semesters from April 1st, 2017 till March 30, 2019) of a statistically significant fraction of all D>100 km main-belt asteroids ( 35 out of 200 asteroids; our survey covers the major compositional classes) at high angular-resolution with VLT/SPHERE throughout their rotation (typically 6 epochs per target). Here, we will present a summary of the results obtained after one year of observations.

Large (D>100km) asteroids are the most direct remnants of the building blocks of planets. (2) Pallas is the third largest asteroid and the parent body of a small collisional family. Its spectral properties indicate a B-type surface, meaning Pallas is most likely linked to carbonaceous chondrite meteorites. Disc-resolved images have revealed a nearly hydrostatic shape overprinted by long-wavelength concavities (Schmidt et al. 2009, Carry et al. 2010). This was interpreted as evidence for an early phase of internal heating subsequent to Pallas's formation, followed by several large impact craters (Schmidt & Castillo-Rogez 2012). Recent estimates of Pallas's density, 2.40±0.25 g.cm^-3 (Schmidt et al. 2009), 3.40±0.90 g.cm^-3 (Carry et al. 2010) and 2.72±0.17 g.cm^-3 (Hanus et al. 2017), are rather inconsistent and prevent from differentiating among the various models proposed for its internal structure (Schmidt & Castillo-Rogez 2012). This currently limits our understanding of the formation and thermal evolution of Pallas. We report new high-angular resolution observations of Pallas collected in the frame of the SPHERE large survey of the asteroid belt (see Talk by P. Vernazza) with the adaptive-optics-fed SPHERE+ZIMPOL camera on the VLT. 40 images acquired at 8 epochs provide a full longitudinal coverage of Pallas's southern hemisphere, with Pallas being resolved with ~120 pixels along its longest axis. The optimal angular resolution of each image was restored with Mistral (Fusco et al. 2002), a myopic deconvolution algorithm optimised for images with sharp boundaries, which allows the identification of many craters and geological features on Pallas. A precise 3D-shape reconstruction was achieved with the ADAM software (Viikinkoski et al. 2015), providing a high precision estimate of Pallas's 3D shape, volume and hence density. Those are used to explore Pallas's early thermal evolution, its subsequent collisional evolution, and its current internal structure and composition. [1] Carry et al. 2010, Icarus, 205, 460 [2] Fusco et al. 2002, SPIE, 4839, 1065 [3] Hanus et al. 2017, A&A, 601, A114 [4] Schmidt et al. 2009, Science, 326, 275 [5] Schmidt & Castillo-Rogez, Icarus, 218, 478 [6] Viikinkoski et al. 2015, A&A, 576, A8

Asteroid (16) Psyche is the target of the NASA Psyche mission. It is considered as one of the few main-belt bodies that could be an exposed proto-planetary metallic core and that would thus be related to iron meteorites. Such association is however challenged by both its near- and mid-infrared spectral properties (e.g. Hardersen et al. Icarus 175, 2005; Takir et al. AJ, 153, 2017; Landsman et al. Icarus, 304, 2018). We observed (16) Psyche with ESO VLT SPHERE/ZIMPOL as part of our large program (ID 199.C-0074, PI Vernazza) between April 24 and June 6 2018. We use the high-angular resolution of these observations to reconstruct the 3D shape model of Psyche. When combined with the most recent estimates of its mass, the volume that we derive led to a bulk density of 3.99 ± 0.26 g.cm^-3 for Psyche. While such density is incompatible at the 3-sigma level with any iron meteorites (~7.8 g.cm^-3), it appears fully consistent with that of stony-iron meteorites such as mesosiderites (density ~4.25 g.cm^-3). Although our observations only covered the northern hemisphere of Psyche, they reveal the presence of two peculiar units in the front views, namely one low and one high brightness regions nicknamed Panthia and Meroe. Meroe unit is about 7% brighter than the surrounding region, whereas the Panthia unit is 8% fainter. Panthia is a depression with a width of 90 km and a depth of 10 km. We did not detect any moons around Psyche and estimate the minimum radius of a moon to be detected around Psyche to 730 ± 100 m at 150 km (so 0.2% x R_Hill) of the primary and 400 ± 100 m at 2000 km from the primary corresponding to 3% x R_Hill) where most of the satellites of >100-km asteroids have been seen so far (Yang et al. AJL 820:L35, 2016). Considering that the visible and near-infrared spectral properties of mesosiderites are similar to those of Psyche, there is merit to the initial hypothesis by Davis et al. (1999) that Psyche could be a plausible candidate parent body for mesosiderites (Viikinkoski et al. submitted to A&A, 2018). This material is based upon work partially supported by the National Science Foundation under Grant No 1743015.

As part of our ESO large program (ID 199.C-0074), we observed asteroid (7) Iris with the VLT/SPHERE/ZIMPOL instrument throughout its rotation during two consecutive nights in October 2017 (five different epochs). Iris, which is one of the four D>200 km S-type main belt asteroids along with (3) Juno, (15) Eunomia and (29) Amphitrite, is an exceptional target for an adaptive optics (AO) campaign due to its large angular size as seen from the Earth (0.35'') during opposition. Considering the large size of Iris, one pixel represents 2.3 km at distance of Iris on our AO images. We identified several topographic features in the ZIMPOL AO images that we interpreted as impact craters. Crater identification was performed manually on the images, by looking for circular features with a clear brightness contrast. Craters were first extracted on each of the five epochs. We compared all the images within a given epoch to confirm the genuineness of the identified features, removing the possibility that they are deconvolution artifacts. In the end, we checked the pairing of craters between the different epochs, that lead to a total number of six individual craters with diameters larger than 20 km. We compared the number and size of the identified craters to the cratering records on Ceres and Vesta. We used the well established ADAM (All-Data Asteroid Modeling) inversion technique for the reconstruction of a highly-detailed 3D shape model (craters included), volume and the spin of Iris using its disk-integrated data (optical lightcurves) and disk-resolved images as inputs. We also estimated the bulk density to 2.4±0.3 g.cm^-3. No moons were identified in our images. This work was supported by the grant 18-09470S of the Czech Science Foundation.

Differentiated asteroids are rare in the main asteroid belt despite evidence for ~100 distinct differentiated bodies in the meteorite record. We have sought to understand why so few main belt asteroids differentiated and where those differentiated bodies or fragments reside. Using the Sloan Digital Sky Survey (SDSS) to search for a needle in a haystack we identify spectral A-type asteroid candidates, olivine-dominated asteroids that may represent mantle material of differentiated bodies. We have performed a near-infrared spectral survey with SpeX on the NASA IRTF and FIRE on the Magellan Telescope. The success rate for confirming A-types from SDSS candidates is 33% - 20 of the 60 objects observed. We report results from having doubled the number of known A-type asteroids. We deduce a new estimate for the overall abundance and distribution of this class of olivine-dominated asteroids. We find A-type asteroids account for less than 0.16% of all main-belt objects larger than 2 km and estimate there are a total of 600 A-type asteroids above that size. They are found rather evenly distributed throughout the main belt, are even detected at the distance of the Cybele region, and have no statistically significant concentration in any asteroid family. We conclude the most likely implication is the few fragments of olivine-dominated material in the main belt did not form locally, but instead were implanted as collisional fragments of bodies that formed elsewhere.

"Where do meteorites come from?" has been an enduring question in planetary science, placing "traceability" (e.g. sample return) at the forefront of current exploration. Towards this goal, orbits for 2 dozen recovered meteorite falls have been determined by dedicated teams over many decades. Herewith we now add the orbits for more than 1000 near-Earth asteroids (NEAs) for which we have telescopic spectral measurements [1] sufficient to make meteorite analog assessments. For hundreds of these NEAs, their meteorite analogs have a high degree of confidence to specific classes (e.g. H, L, LL chondrites) based on detailed mineralogical modeling [2] tested against the ground truth from the Hayabusa mission [3]. As independent variables, we correlate each NEA's meteorite analog with its dynamical source region derived from the models by Granvik et al. [4,5] accounting for Yarkovsky drift and resonance delivery efficiencies. When ratioed to the overall flux rate for the diffusion of main-belt asteroids into the inner solar system, distinct source region signatures emerge for all major meteorite classes. Most interestingly, a high degree of correlation is found with respect to the compositional gradient in the asteroid belt [6,7], with the most primitive classes preferring an outer belt or Jupiter Family Comet origin. We integrate all of these results together into a new "Big Picture" view of where the major classes of meteorites come from. Observational data used in this research were obtained using the NASA Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration. This work supported by the National Science Foundation Grant 0907766 and NASA Grant NNX10AG27G. References: [1] Binzel et al. (2018), Submitted to Icarus. [2] Shkuratov et al. (1999). Icarus137, 222. [3] Nakamura et al. (2011). Science 333,1113. [4] Granvik et al. (2018). Icarus312, 181. [5] Granvik, M., Brown, P. (2018). Icarus311, 271. [6] Gradie, J., Tedesco, E.F. (1982). Science216, 1405. [7] DeMeo, F. E., Carry, B. (2014). Nature505, 629.

The Europlanet H2020 program started on 1/9/2015 for 4 years. It includes an activity to adapt Virtual Observatory (VO) techniques to Planetary Science data called VESPA. The objective is to facilitate searches in big archives as well as sparse databases, to provide simple data access and on-line visualization, and to allow small data providers to make their data available in an interoperable environment with minimum effort. The VESPA system, based on a prototype developed in a previous program [1], has been hugely improved during the first two years of Europlanet H2020: the infrastructure has been upgraded to describe data in many fields more accurately; the main user search interface (http://vespa.obspm.fr) has been redesigned to provide more flexibility; alternative ways to access Planetary Science data services from VO tools have been implemented; VO tools are being improved to handle specificities of Solar System data, e.g. measurements in reflected light, coordinate systems, etc. Current steps include the development of a connection between the VO world and GIS tools, and integration of Heliophysics, planetary plasmas, and mineral spectroscopy data to support of the analysis of observations. Existing data services have been updated, and new ones have been designed. The global objective is already overstepped, with 34 services open and 20 more being finalized. A procedure to install data services has been documented, and hands-on sessions are organized twice a year at EGU and EPSC; this is intended to favour the installation of services by individual research teams, e.g. to distribute derived data related to a published study. In complement, regular discussions are held with big data providers, starting with space agencies (IPDA). Common projects with ESA and NASA's PDS have been engaged, with the goal to connect PDS4 and EPN-TAP. In parallel, a Solar System Interest Group has just been started in IVOA; the goal is here to adapt existing astronomy standards to Planetary Science. The Europlanet 2020 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208. [1] Erard et al 2014, Astronomy & Computing 7-8, 71-80.

ESO allocated to our Large Asteroid Survey with SPHERE (LASS) program 152 hours of observations over four semesters (PI: Pierre Vernazza, run ID: 199.C-0074) to carry out disk-resolved images of 38 large (D>100 km) main-belt asteroids (sampling the four main compositional classes) at high angular- resolution with VLT/SPHERE throughout their rotation in order to derive their 3-D shape, the size distribution of the largest craters, and their density. Here we focus on the analysis of SPHERE data taken in July 2017 of the triple asteroid (216) Kleopatra. Two tiny moons (3 & 5 km diameter) were discovered in September 2008 around the large (equivalent radius 67.5 ± 2.9 km) M-type asteroid orbiting very close to the irregularly shaped primary at 300 and 700 km respectively (Descamps et al. 2010). With these additional data, our goals are i) to refine the average density of this interesting M-type asteroid ii) estimate its interior structure by detecting precession effects between the satellites iii) detect the presence of an additional moon which was suspected in W.M. Keck AO observation taken back in 2008. We will present this new data set, their analysis and new conclusion on the origins and formation of this asteroid.

ESO allocated to our Large Asteroid Survey with SPHERE (LASS) program 152 hours of observations over four semesters (PI: Pierre Vernazza, run ID: 199.C-0074) to carry out disk-resolved images of 38 large (D>100 km) main-belt asteroids (sampling the four main compositional classes) at high angular-resolution with VLT/SPHERE throughout their rotation in order to derive their 3-D shape, the size distribution of the largest craters, and their density. LASS program is introduced in more details by Marchis et al. in this session. Here we focus on the preliminary shape modeling of a few individual asteroids that were targeted in the first semester of the LASS program by the SPHERE Extreme AO system. To obtain the 3D shape model with a local topography, we utilize the All-Data Asteroid modelling (ADAM, Viikinkoski et al. 2015, A&A, 576, A8) procedure that allows simultaneous inversion of optical lightcurves, stellar occultations and disk-resolved images. Because ADAM minimizes the difference between the Fourier transformed image and a projected polyhedral model, we do not require any a priori extraction of boundary contours. Utilization of AO images allows ADAM to scale the shape model in size, which essentially leads to a volume estimate.We derive preliminary shape models for selected asteroids and compare them with models based on disk-resolved images obtained by the Near InfraRed Camera (Nirc2) mounted on the W. M. Keck II telescope. We illustrate the performance of the ADAM procedure and the shape model improvement due to the unprecedented quality of the SPHERE images.

Asteroids in our solar system are metallic, rocky and/or icy objects, ranging in size from a few meters to a few hundreds of kilometers. Whereas we now possess constraints for the surface composition, albedo and rotation rate for all D?100 km main-belt asteroids, the 3-D shape, the crater distribution, and the density have only been measured for a very limited number of these bodies (N?10 for the first two). Characterizing these physical properties would allow us to address entirely new questions regarding the earliest stages of planetesimal formation and their subsequent collisional and dynamical evolution.ESO allocated to our program 152 hours of observations over 4 semesters to carry out disk-resolved observations of 38 large (D>100 km) main-belt asteroids (sampling the four main compositional classes) at high angular-resolution with VLT/SPHERE throughout their rotation in order to derive their 3-D shape, the size distribution of the largest craters, and their density (PI: P. Vernazza). These measurements will allow investigating for the first time and for a modest amount of observing time the following fundamental questions: (A) Does the asteroid belt effectively hosts a large population of small bodies formed in the outer solar system? (B) Was the collisional environment in the inner solar system (at 2-3 AU) more intense than in the outer solar system (>5AU)? (C) What was the shape of planetesimals at the end of the accretion process?We will present the goals and objectives of our program in the context of NASA 2014 Strategic Plan and the NSF decadal survey "Vision and Voyages" as well as the first observations and results collected with the SPHERE Extreme AO system. A detailed analysis of the shape modeling will be presented by Hanus et al. in this session.

Since October 2016, the short term (ST) processing of Solar System Objects (SSOs) by Gaia is up and running, and it has produced almost 600 alerts. A crucial point in the chain is the possibility of performing a short arc orbit determination as soon as the object has been detected, which allows the follow up of the object from the ground.The method we present has been recentely developed for two mainreasons: 1) search for imminent impactors within the NEO - Confirmation Page(imminent impactors are asteroids that could impact the Earth infew days from their discovery) 2) validation of the SSO-ST Gaia pipeline.We show some good confirmations on objects that could have been discovered by Gaia, and some properties of the Gaia astrometry for the short term.

SuperWASP consists of two telescopes, North and South, located at La Palma and the South African Astronomical Observatory respectively. It was designed as a survey for transiting exoplanets, covering the period from 2004 to 2014. In order to detect the maximum number of exoplanet transit detections, it has a large field of view (7.8 x 7.8 degrees) and observes the same patch of sky for weeks at a time, which means that any asteroids that enter the field of view will likely stay in it for many weeks. It has a limiting magnitude of V < 15 which allows most of the large bodies in the main belt to be detected. Shape models require the asteroid to be viewed from multiple angles, and have lightcurves that contain features characteristic of the body. As asteroids often stay in the field of view of SuperWASP for a month, and appear in multiple years of the dataset, it is a very good source of lightcurves for shape modelling and phase curves.

The known number of minor bodies in our Solar System keeps increasing with a totaling of more than 725,000 asteroids as of Dec 11, 2016. Likewise our knowledge of their physical properties does (e.g. more than 138,000 asteroids have known sizes). Interestingly, physical and dynamical studies of these bodies are becoming more interconnected to each other: For instance, the dynamical evolution of km-sized asteroids is affected by non gravitational forces, which depend on the physical properties of the bodies, such as size, spin state, shape, and thermal inertia. In addition, the study of asteroid families requires precise knowledge of the spectral class (or color), albedos, and sizes, along the orbital elements of these bodies. Moreover, it has been shown how the orbital distribution of the compositional classes throughout the Main belt can inform us about the past migration of the planets.
While the computation, and archival of orbits from the astrometric observations is performed in a very organized fashion by the MPC, JPL, and Ast/Neo-Dys, there is no such service that collects, analyses, and make a synthesis of the properties of minor bodies.
Here we present the Minor Planet Physical Properties Catalogue (mp3c.oca.eu) hosted at the Observatoire de la Cote d’Azur in Nice, France.

Introduction: The preparation of a detailed night schedule prior to an observing run can be tedious, especially for solar system objects which coordinates are epoch-dependent. Several tools generating airmass charts and all-sky fish-eye graphics are freely available to the community. The staralt pages, by J. Méndez, or the skycalc software, maintained by J. Thorstensen, represents an easily-portable and interactive solution to these points. Yet, these tools have been developed for objects with fixed coordinates, and the eight planets. Planning observations of moving Solar System Objects (SSOs) may therefore result impracticable: one should compute first the coordinates of each object, and then enter them into the software interface. This often results impossible if the list of targets is long, or many dates are envisioned.

ViSiON: We aim at providing the community with a Web service compliant with Virtual Observatory (VO) standards, to create tables of observing conditions, together with airmass and sky charts, for an arbitrary list of targets, including SSOs. We achieve this by taking advantage of available VO services such as the SIMBAD astronomical database, the Aladin sky atlas, and the Miriade ephemerides generator to build a new service dedicated to the planning of observations. This new service, dubbed ViSiON for Visibility Service for Observing Nights, is a new method of Miriade [1] Web service hosted at IMCCE. It allows anyone to create, via a very simple interface, graphics of observing conditions (Figs 1 and 2) and tables summarizing them, provided as PDF, VOTable, and xHTML documents.

Interoperability: To help further the observers, ViSiON provides dedicated links to other VO services for each target. In particular, it can 1) open the Aladin Sky Atlas in a Web browser, displaying all the known SSOs in a radius of a few arcminutes, and 2) generate on the fly detailed ephemerides for the entire night with short time steps for the need of telescope pointing.

Acknowledgments: This development of this service was partly funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.

Introduction: The ESA Euclid mission will conduct a visible and near-infrared imaging and spectroscopic survey over 15,000 deg², down to a magnitude of V_AB~24.5, with an HST-like angular resolution. Although the survey design will avoid ecliptic latitudes below 15°, the imaging sequence, in repeated sequences of four broad-band filters, seems well-adapted to Solar System objects (SSOs) detection and characterization.

ESA Euclid: Euclid is a survey telescope equipped with a 1.2 m-diameter primary mirror, and two instruments: a VISible imaging camera and a Near Infrared Spectrometer and Photometer (VIS and NISP). Euclid will carry out an imaging and spectroscopic survey of the extra-galactic sky of 15,000 deg², avoiding galactic latitudes smaller than 30° and ecliptic latitudes below 15°. About 7000 observations of calibration fields, including ~300 close to the ecliptic plane, will also be conducted. The surveys will consist in a step-and-stare tiling mode, in which both instruments observe the same 0.57 deg² Field of View (FoV) on the sky. An observing sequence will consist in a simultaneous VIS-imaging - NISP-spectroscopy 565s exposure followed by three ~100s-long NISP-imaging exposures (Y, J, H filters), repeated four times with a dither pattern.

Observations of solar system objects: We estimate the number of SSOs that will be observed by Euclid by 1) extrapolating currentpopulation by power laws, and 2) estimating the fraction of known SSOs within the limits of Euclid survey. About 10⁵ SSOs should be detected with Euclid, with additional 105 in calibration fields.

Expected science: For each SSO fortuitly present in Euclid FoV, its position and apparent magnitude in VIS (large g+r+i filter), Y, J, and H will be measured four times, providing 1h10-long lightcurves and VIS-NIR color indices. These short lightcurves can be used together with Gaia/LSST sparse photometry to constrain period, spin, and 3-D shape models of asteroids. The most-promising science case is however the taxonomy of SSOs, for which the NIR colors of Euclid will conveniently complete the visible colors from, e.g., Gaia and LSST.

The presentation concerns a novel asset for spectroscopy of Near-Earh Asteroids, which will be installed in Pic du Midi Observatory, in France.

High resolution spectral observations of small S-type and Q-type Near Earth Asteroids (NEAs) have shown two important trends. The spectral slope of these asteroids, which is a good indication of the amount of space weathering the surface has received, has been shown to decrease with decreasing perihelion and size. Specifically, these trends show that there are less weathered surfaces at low perihelion and small sizes. With recent results from all-sky surveys such as the Sloan Digital Sky Survey's (SDSS) Moving Object Catalog, we have gained an additional data set to test the presence of these trends in the NEAs as well as the Mars Crossers (MCs) and the Main Belt. We use an analog to the spectral slope in the SDSS data which is the slope through the g', r' and i' filters, known as the gri-slope, to investigate the amount of weathering that is present among small asteroids throughout the inner solar system. We find that the trend of the gri-slope decreases with decreasing size at nearly the same rate in the Main Belt as in the MC and NEA regions. We propose that these results suggest a ubiquitous presence of Q-types and S-types with low spectral slopes at small sizes throughout the inner solar system, from the Main Belt to the NEA region. Additionally, we suggest that the trend of decreasing spectral slope with perihelion may only be valid at perihelia of approximately less than 1 AU. These results suggest a change in the interpretation for the formation of Q-type asteroids. Planetary encounters may help to explain the high fraction of Q-types at low perihelia, but another process which is present everywhere must also be refreshing the surfaces of these asteroids. We suggest the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect as a possible mechanism.

The existence of iron meteorite samples suggest that a number of planetesimals differentiated fully and were subsequently disrupted. Within the current asteroid belt, there is little evidence of bodies that fully differentiated into core, mantle and crust layers (Moskovitz et al. 2008). However, because it has been suggested that differentiation can occur within the interior of a body while the primitive exterior remains intact (Elkins-Tanton et al. 2011), an understanding of the diversity of compositions from differentiated parent bodies is critical. Asteroid families, as constituents of a disrupted progenitor body, provide a glimpse into the interior of their progenitors. However, asteroid families, while spectrally unique from one another, are spectrally similar within each family (Parker et al., 2008, Masiero et al. 2011). Using the Sloan Digital Sky Survey (SDSS) to search for a "needle in a haystack" we identify candidate basaltic and olivine-rich asteroids that are dynamically associated with asteroid families to constrain the amount of differentiation that could have occurred within the parent asteroid. Using FIRE on the 6-meter Magellan Telescope and SpeX on the 3-meter IRTF Telescope we measure near-infrared spectra of more than thirty of these candidates, most of which are part of the Eunomia and Flora families. Results of these observations are presented in this talk.

(6) Hebe is a large main-belt asteroid, accounting for about half a percent of the mass of the asteroid belt. Its spectral characteristics and close proximity to dynamical resonances within the main-belt (the 3:1 Kirkwood gap and the nu6 resonance) make it a probable parent body of the H-chondrites and IIE iron meteorites found on Earth.We present new AO images of Hebe obtained with the high-contrast imager SPHERE (Beuzit et al. 2008) as part of the science verification of the instrument. Hebe was observed close to its opposition date and throughout its rotation in order to derive its 3-D shape, and to allow a study of its surface craters. Our observations reveal impact zones that witness a severe collisional disruption for this asteroid. When combined to previous AO images and available lightcurves (both from the literature and from recent optical observations by our team), these new observations allow us to derive a reliable shape model using our KOALA algorithm (Carry et al. 2010). We further derive an estimate of Hebe's density based on its known astrometric mass.

Polarimetry constitutes one of the fundamental tools for characterizing the surface texture and composition of airless Solar System bodies. In 2006, polarimetric observations led to the discovery of a new type of asteroids, which displays a peculiar polarimetric response. These asteroids are collectively known as "Barbarians", from (234) Barbara the first discovered one.The most commonly accepted explanation for this perculiar polarization response seems to be the presence of a high percentage of fluffy-type Calcium Aluminium-rich Inclusions (CAIs), whose optical properties could produce the observed polarization. Their reflectance spectra also exibit an absorption feature in the near-infrared around 2.1-2.2 microns, that is characteristic of this peculiar group.Based on these results, we organized a systematic polarimetric and near-infrared observational campaign of known Barbarians or candidate asteroids. These campaigns include members of the family of 1040 Klumpkea, 2085 Henan and 729 Watsonia, which are known to contain Barbarian and/or L-type asteroids also suspected to have such a polarimetric behaviour. We have made use of the ToPo polarimeter at the 1m telescope of the Centre pédagogique Planète et Univers (C2PU, Observatoire de la Côte d'Azur, France). The spectroscopic observations in the near-infrared were obtained with the SpeX instrument at the NASA's InfraRed Telescope Facility (IRTF).By combining polarimetry and spectroscopy we find a correlation between the abundance of CAIs and the inversion angle of the phase-polarization curve of Barbarian asteroids. This is the first time that a direct link has been established between a specific polarimetric response and the surface composition of asteroids. In addition, we find a considerable variety of CAI abundance from one object to the other, consistent with a wide range of possible albedos. Since these asteroids constitute a reservoir of primitive Solar System material, understanding their origin can shed light on the processes driving the formation and transport of the refractory minerals that first condensed in the protoplanetary disk.

The Gaia ESA space mission will provide astrometric observations of a large number of celestial bodies, with unprecedented accuracy, and in an homogenous reference frame (to become the optical ICRF). The Gaia satellite is monitoring regularly the whole celestial sphere, with one complete scan in about 6month, down to approximately magnitude V?20.7. It will provide after its nominal lifetime, (5 years, 2014-2019) about 70 astrometric points for several hundred thousands of solar system objects, asteroids from the Near-Earth region to Centaurs and bright TNOs, as well as planetary satellites and comets. The highly precise astrometric and photometric data is bound to lead to huge advances in the science of small Small Solar System Bodies (e.g. Tanga et al. 2016 P&SS, Hestroffer et al. 2014 COSPAR #40 ; Mignard et al. 2007 EMP).The first Gaia data release (GDR#1) is foreseen for Q3-2016 and will provide highly precise positions of selected stars down to mag V~20. While solar system objets data is foreseen for the next data release (in 2017), science of Solar System will also highly benefit from the Gaia stellar catalogue. We will present the status of the satellite and Gaia mission, and details on the stellar data that will be published in this GDR#1. We discuss the catalogue content, number of stars, parameters and precisions, and the process of cross-matching and validation. We also touch upon the construction of combined Tycho-Gaia TGAS catalogue.A Gaia data daily processing is devoted to the identification of Solar System Objects. During this process the detection of new (or critical) objects arises and leads to the triggering of scientific alerts to be found on the web gaiafunsso.imcce.fr. We have also set up an international follow-up network called Gaia-FUN-SSO to validate the detection in space. For this goal, in case of detection the observational data must be sent to the MPC by the observers. Besides, Gaia should benefit for the classical astrometric reduction, for future as well as for past observations, which is part of the NAROO project (Robert et al. 2015 A&A). We will also touch upon the next releases steps, and the SSO data from Gaia observations that will be published.

The Ground Based Optical Tracking group (GBOT) consists of about ten scientists involved in the Gaia mission by ESA. Its main task is the optical tracking of the Gaia satellite itself [1]. This novel tracking method in addition to radiometric standard ones is necessary to ensure that the Gaia mission goal in terms of astrometric precision level is reached for all objects. This optical tracking is based on daily observations performed throughout the mission by using the optical CCDs of ESO's VST in Chile, of Liverpool Telescope in La Palma and of the two LCOGT's Faulkes Telescopes in Hawaii and Australia. Each night, GBOT attempts to obtain a sequence of frames covering a 20 min total period and close to Gaia meridian transit time. In each sequence, Gaia is seen as a faint moving object (Rmag ~ 21, speed > 1"/min) and its daily astrometric accuracy has to be better than 0.02" to meet the Gaia mission requirements. The GBOT Astrometric Reduction Pipeline (GARP) [2] has been specifically developed to reach this precision.More recently, a secondary task has been assigned to GBOT which consists detecting and analysing Solar System Objects (SSOs) serendipitously recorded in the GBOT data. Indeed, since Gaia oscillates around the Sun-Earth L2 point, the fields of GBOT observations are near the Ecliptic and roughly located opposite to the Sun which is advantageous for SSO observations and studies. In particular, these SSO data can potentially be very useful to help in the determination of their absolute magnitudes, with important applications to the scientific exploitation of the WISE and Gaia missions. For these reasons, an automatic SSO detection system has been created to identify moving objects in GBOT sequences of observations. Since the beginning of 2015, this SSO detection system, added to GARP for performing high precision astrometry for SSOs, is fully operational. To this date, around 9000 asteroids have been detected. The mean delay between the time of observation and the submission of the SSO reduction results to the MPC is less than 12 hours allowing rapid follow up of new objects.[1] Altmann et al. 2014, SPIE, 9149.[2] Bouquillon et al. 2014, SPIE, 9152.

The ESA Gaia mission, currently surveying the sky from the L2 Lagrangian Point, is providing astrometry of stars and asteroids, at the sub-milliarcsec accuracy. However, the exploitation of this unprecedented capacity of investigation, requires to tackle some specific issues, mostly related to the peculiar properties of the Gaiadata.Orbit determination and improvement have to be tuned at several levels, from the preliminary short-arc solution, up to the most extreme dynamical modeling taking into account observations on a long time span. More specifically, asteroid positions determined by Gaia are very accurate in one direction only, and are affected by a large correlation of the uncertainties in the equatorial coordinates. In order to make the best possible exploitation of Gaia astrometry, we are adapting the software tools to correctly take into account suchcorrelation. We will discuss preliminary results obtained while validating our approach on some asteroid observations by Gaia, that provide for the first time a quantitative evaluation of the reachable accuracy onreal data.In particular, we will discuss the contribution of Gaia relative to the whole available record of observations, and the differences found in the accuracy of alerts (daily processing) with respect to the exploitation of better calibrations. The impact of the first Gaia data release (GDR1) and following on the prediction of stellar occultations by asteroids, is also addressed.

Since the start of its regular observing program in summer 2014, the Gaia mission has carried out systematic photometric, spectrometric, and astrometric observations of asteroids. In total, the unique capabilities of Gaia allow for the collection of an extensive and homogeneous data set of some 350,000 asteroids down to the limiting magnitude of G = 20.7 mag. The Gaia performance remains excellent over the entire available brightness range. Starting from 2003, a working group of European asteroid scientists has explored the main capabilities of the mission, defining the expected scientific impact on Solar System science. These results have served as a basis for developing the Gaia data reduction pipeline, within the framework of the Data Processing and Analysis Consortium (DPAC). We describe the distribution of the existing and forecoming Gaia observations in space and time for different categories of objects. We illustrate the peculiar properties of each single observation, as these properties will affect the subsequent exploitation of the mission data. We will review the expected performances of Gaia, basically as a function of magnitude and proper motion of the sources. We will further focus on the areas that will benefit from complementary observational campaigns to improve the scientific return of the mission, and on the involvement of the planetary science community as a whole in the exploitation of the Gaia survey. We will thus describe the current and future opportunities for ground-based observers and forthcoming changes brought by Gaia in some observational approaches, such as stellar occultations by transneptunian objects and asteroids. We will show first results from the daily, short-term processing of Gaia data, all the way from the onboard data acquisition to the ground-based processing. We illustrate the tools developed to compute predictions of asteroid observations, we discuss the procedures implemented by the daily processing, and we illustrate some tests and validations of the processing of the asteroid observations. Overall, our findings are consistent with the expectations from the performances of Gaia and of the subsequent data reduction. As to the long-term processing of Gaia data, we expect to derive masses, sizes, average densities, spin properties, reflectance spectra, albedos, as well as new taxonomic classifications for large numbers of asteroids. In this review, we will describe the prospects for Gaia photometry and spectrophotometry. We will describe inverse methods for sparse photometric data using the so-called Lommel-Seeliger ellipsoids. We will further describe the modeling of Gaia spectra for the compositional studies of asteroids, as well as the prospects for a new Gaia asteroid taxonomy. Gaia data will open a new era in asteroid science, allowing us to answer fundamental questions concerning, for example, the interrelation between asteroid internal structure and surface properties.

After a commissioning period, the astrometric mission Gaia of the European Space Agency (ESA) started its survey in July 2014. Throughout passed two years the Gaia Data Processing and Analysis Consortium (DPAC) has been treating the data. The current schedule anticipates the first Gaia Data Release (Gaia-DR1) toward the end of summer 2016. Nevertheless, it is not planned to include Solar System Objects (SSO) into the first release. This is due to a special treatment required by solar system objects, as well as by other peculiar sources (multiple and extended ones). In this presentation, we address issues and recent achivements in SSO processing, in particular validation of SSO-short term data processing chain, GAIA-SSO alerts, as well as the first runs of SSO-long term pipeline.

The ratio of crust to mantle material in the asteroid belt indicates that these bodies originate as ejecta from giant impacts on the growing terrestrial planets.

Olivine-dominated asteroids, classified as A-types with near-infrared spectral measurements are largely thought to be the mantle remnants of disrupted differentiated small bodies. These A-type asteroids hold clues to asteroid differentiation and to the collisional history of those differentiated bodies. Preliminary studies of the abundance and distribution of A-type asteroids were performed by Carvano et al. (2010) and DeMeo & Carry (2013, 2014) using the Sloan Digital Sky Survey (SDSS). To confidently identify these olivine-dominated A-type asteroids, however, near-infrared spectral measurements are needed to identify the distinct broad and deep 1-micron olivine absorption feature. Using the Sloan Digital Sky Survey Moving Object Catalog to select A-type asteroid candidates, we have performed a near-infrared spectral survey of over 70 asteroids with SpeX on the IRTF. We present the abundance and distribution of A-type asteroids throughout the main asteroid belt and compare these results with similar surveys for basalt-rich V-type asteroids (e.g. Moskovitz et al. 2008). This work is supported by NASA under grant number NNX12AL26G issued through the Planetary Astronomy Program.

The satellite of the Cybele asteroid (107) Camilla was discovered in March 2001 using the Hubble Space Telescope (Storrs et al., 2001, IAUC 7599). From a set of 23 positions derived from adaptive optics observations obtained over three years with the ESO VLT, Keck-II and Gemini-North telescopes, Marchis et al. (2008, Icarus 196) determined its orbit to be nearly circular.In the new work reported here, we compiled, reduced, and analyzed observations at 39 epochs (including the 23 positions previously analyzed) by adding additional observations taken from data archives: HST in 2001; Keck in 2002, 2003, and 2009; Gemini in 2010; and VLT in 2011. The present dataset hence contains twice as many epochs as the prior analysis and covers a time span that is three times longer (more than a decade).We use our orbit determination algorithm Genoid (GENetic Orbit IDentification), a genetic based algorithm that relies on a metaheuristic method and a dynamical model of the Solar System (Vachier et al., 2012, A&A 543). The method uses two models: a simple Keplerian model to minimize the search-time for an orbital solution, exploring a wide space of solutions; and a full N-body problem that includes the gravitational field of the primary asteroid up to 4th order.The orbit we derive fits all 39 observed positions of the satellite with an RMS residual of only milli-arcseconds, which corresponds to sub-pixel accuracy. We found the orbit of the satellite to be circular and roughly aligned with the equatorial plane of Camilla. The refined mass of the system is (12 ± 1) x 10¹⁸ kg, for an orbital period of 3.71 days.We will present this improved orbital solution of the satellite of Camilla, as well as predictions for upcoming stellar occultation events.

We will present the first results from a magnitudelimited survey of over 60 Kuiper belt objects (KBOs) observed within a Large Program at the 3.6-m ESO New Technology Telescope (NTT). The multi-band observations are used to obtain lightcurves for targets from all KBO dynamical classes. We are aiming to derive the individual targets' physical and rotational characteristics as well as to use the bulk properties of the different KBO populations as sources of information for their formation mechanisms and collisional history.

On the 19th of December 2013, the Gaia spacecraft was successfully launched by a Soyuz rocket from French Guiana and started its amazing journey to map and characterize one billion celestial objects with its one billion pixel camera. In this presentation, we briefly review the general goals of the mission and describe what has happened since launch, including the Ecliptic Pole scanning mode. We also focus especially on binary stars, starting with some basic observational aspects, and then turning to the remarkable harvest that Gaia is expected to yield for these objects.

After its successful launch in December 2013, and commissioning period, ESA's astrometric space mission Gaia has now started its scientific operations. In addition to the 3D census of our Milky Way with high precision parallax, proper motion, and other parameters derived for a billion of stars, Gaia will also provide a scientific harvest for Solar System Objects (SSO) science. The high precision astrometry and photometry that will be regularly collected for about 300,000 asteroids - during the 5years nominal mission time - will enable significant improvements on fundamental observational data for a very large number of objects.I will describe the current status of the satellite and observations, the Gaia-FUN-SSO follow-up network, data releases policy, and data validations. We will also present the expected results on the dynamics of asteroids and comets, asteroid masses and binary asteroids, tests of GR, and prospects of SSO science (satellites, stellar occultations, etc.) with the Gaia stellar catalogue.Acknowledgements: Thanks to the Gaia DPAC CU4 consortium, and the Labex ESEP (No 2011-LABX-030) & Initiative d'excellence PSL* (convention No ANR-10-IDEX-0001-02)

The trans-Neptunian 136108 Haumea is a very fast rotator (~3.9h). It also displays a highly elongated shape and hosts two small moons, all covered with crystalline water ice, similarly to their central body. Haumea is also known to be the largest member of a TNO family, itself the outcome of a catastrophic collision likely responsible for Haumea's unique characteristics.We report here on the analysis of a new set of near-infrared Laser Guide Star assisted observations of Haumea obtained with the IFU spectrograph SINFONI at the ESO-Very Large Telescope Observatory. Combined with previous data published by Dumas et al. (2011), and using photometric light curve measurements (Lacerda 2009, Lellouch et al. 2011) to associate each spectrum with Haumea's corresponding rotational phase, we were able to derive an accurate rotationally resolved spectroscopic study of the surface of this trans-neptunian. A particular region of interest was the dark-red spot identified on the surface of Haumea from multi-band light curve analysis (Lacerda et al. 2008). We will present the results of applying Hapke modeling to our data-set, and our conclusions regarding the surface heterogeneity of Haumea. Additionally, thanks to the IFU capabilities to reconstruct images from our spectral cube, we were able to obtain relative astrometric position measurements for the two satellites and constrain dynamical models for their orbital motion.

In the frame of the DPAC consortium preparing the Gaia mission, a specific follow-up activity has been set up in order to ensure best scientific return related to solar-system-object (SSO) science. This activity encompasses a system of alerts for newly detected objects provided by CNES, the French data center in charge of the Solar System data processing, and IMCCE, to organize and publish the alerts, and to retrieve the objects astrometry and feed the Minor Planet Center database.
We are expecting in particular the detection of new near-Earth objects (NEO) at low solar elongation, or even inner-Earth objects. Owing to its observing mode, the satellite will not be able to monitor these objects after discovery and they could be lost. It is thus important to consolidate and improve their orbital parameters. This is the objective of the SSO ground-based follow-up. Once the objective is reached, it is possible to update the auxiliary database of orbital elements used within the Gaia data reduction pipeline for identifying the known SSOs and to allow Gaia to subsequently identify these objects properly during its mission.
In order to reach these goals we have carried out two main activities: -- We have developed a pipeline for processing the Gaia raw data that will be received, and for disseminating only the topocentric data useful for observers in an automatized way -- We have set up a worldwide network of observing stations, the Gaia-FUN-SSO network (shortly described at https://www.imcce.fr/gaia-fun-sso/). At this date, 55 observing sites have registered and many participants have already contributed to several training campaigns for NEO observations.
We will describe both activities and we will give preliminary results regarding the Gaia Solar System alerts, depending on the status of the triggering system during this early stage of the mission.

Density and internal structures are among the most important characteristics of asteroids, yet these properties are also some of the least known. For distant asteroids (in the Main Belt and beyond) these properties were up to now accessible only for the largest (>100 km in size) asteroids. Going to smaller and fainter asteroids can revolutionize our understanding because we will be sampling a new regime in physical properties. Here we discuss how ground-based optical interferometry with the GRAVITY instrument can be used to observe the motion of asteroid satellites to determine the mass of small binary systems. Following the expected sensitivity performances in K-band of GRAVITY, we present a sample of binary targets potentially observable in single-field mode. The feasibility of such observations will strongly be dependent on the ability of the control software of GRAVITY to track objects moving at high rate on the sky (differential motion of 10 mas.s^-1). Although the dual-field mode could allow to increase the sample of small binary asteroids observable, it seems to be currently unfeasible given the high differential motion of asteroids.

The Gaia mission is to be launched on December 19th, 2013 by the European Space Agency (ESA). Solar System science is well covered by the mission and has been included since the early stages of its concept and development. We present here some aspects on the astrometry and dynamics of Solar System Objects (SSO) - in particular asteroids, comets and satellites - as well as ground-based support. We also touch upon the future of SSO astrometry that will be achieved indirectly, after mission completion, from the Gaia astrometric catalogue.

The snowline conventionally divides Solar System objects into dry bodies, ranging out to the main asteroid belt, and icy bodies beyond the belt. Recently, the detection of dust emission from "main-belt comets" and of hydration features and possible water ice absorption on some main-belt asteroids together with theories of migration of small bodies in the solar system cast some doubts on the classical picture. Ceres, contributing about 30 % of the mass of the asteroid belt, is thought to be differentiated into an icy core and a silicate mantle and hydrated minerals were found on infrared spectra of its surface. A marginal detection of OH, a photodissociation product of water was reported in 1991, but questioned by later, more sensitive observations.. Observations of Ceres with the Heterodyne Instrument for the Far Infrared (HIFI) on the Herschel Space Observatory in the context of the MACH 11 guaranteed time program and with a follow up DDT program detected water vapour from Ceres on 3 occasions in 2012 and 2013. The production rate of water on Ceres is a few times 10²⁶-1. The signal from the water vapour from Ceres was found to be linearly polarized during some of the observations, with the absorption being stronger in the horizontal branch. The measured line area ratio of up to 2.5 between H and V polarizations is so far unexplained. The water signal varies on time scales of hours. Those variations are interpreted as localized sources on Ceres surface rotating into and out of the hemisphere visible by Herschel. The time variability is consistent with those sources being dark features known from ground-based adaptive optics observations. The water vapour on Ceres may be either produced by near surface ice heated by sunlight (cometary activity) or by cryovolcanoes or geysers getting their energy from Ceres' interior. In the first case the production rate is expected to peak around perihelion, while for volcanic the time variations are expected to be more stochastic. The existing observations appear consistent with the cometary hypothesis, but do not allow to clearly distinguish between those possibilities. Upon its arrival at Ceres in 2015, the DAWN spacecraft may provide insight into the sources and mechanisms of water production at Ceres.

In order to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO, an observation campaign on the Potentially Hazardous Asteroid (99942) Apophis was conducted from 12/21/2012 to 5/2/2013 providing 2732 high quality astrometric observations. We show that a consistent reduction of astrometric campaigns with reliable stellar catalogs substantially improves the quality of astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029.

During the five years of its all-sky survey, the ESA astrometry mission Gaia is

The Gaia Follow-Up Network for the ground-based follow-up of Solar System Objects (Gaia-FUN-SSO) has been set up starting from 2008. Since this date many participants joined it and several have contributed to training campaigns. Now, almost three months after Gaia came into the operation phase, this network is still awaiting the triggering of Solar System Objects alerts but is ready to react. In this article we recall the structure of the network, the goals and the status of this activity.

In order to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO, an observation campaign on the Potentially Hazardous Asteroid (99 942) Apophis was conducted from 12/21/2012 to 5/2/2013 providing 2732 high quality astrometric observations. We show that a consistent reduction of astrometric campaigns with reliable stellar catalogs substantially improves the quality of astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029.

The ESA astrometry mission Gaia started its operations in June 2014 and will repeatedly scan the entire celestial sphere down to magnitude 20 over the course of its five years mission. About 250,000 solar system objects will be observed, 60 to 80 times each on average, providing an homogeneous high-precision data set of astrometry and photometry for orbit determination and physical properties characterization. We investigate here how many new objects can be detected by Gaia, by extrapolating currently known population toward smaller size down to Gaia apparent limiting magnitude.

Gaia-FUN-SSO (shortly described at https://www.imcce.fr/gaia-fun-sso/) is a ground-based network of observatories set up in the framework of the Gaia consortium (DPAC-CU4) for the follow-up of critical Solar System objects to be discovered from space by the Gaia satellite. Its goal is to retrieve from the ground a newly detected object and to complement the astrometry measurements carried out by Gaia to determine its heliocentric orbit. Data from both Gaia and the ground-based network will be sent to the Minor Planet Center, used to determine the orbit and thus to update the database of minor planet orbits, which is subsequently used by Gaia for the identification of moving objects. We are expecting the detection of many asteroids, mainly from the main belt, and also new near-Earth objects (NEO) at low solar elongation. Owing to the specific conditions of Gaia observations, we even expect the detection of objects whose orbit is fully contained within Earth's orbit (called inner-Earth or Atira asteroids). Several training campaigns have already been organized with the network and it is now able to enter in an operating mode when alerts will be triggered. We describe here the expected number of discoveries, the network, its activity, and the data processing of the central node of the network set in place for the operating mode.

Convex shape models and spin vectors of asteroids are now routinely derived from their disk-integrated lightcurves by the lightcurve inversion method of Kaasalainen et al. (2001, Icarus 153, 37). These shape models can be then used in combination with thermal infrared data and a thermophysical model to derive other physical parameters - size, albedo, macroscopic roughness and thermal inertia of the surface. In this classical two-step approach, the shape and spin parameters are kept fixed during the thermophysical modeling when the emitted thermal flux is computed from the surface temperature, which is computed by solving a 1-D heat diffusion equation in sub-surface layers. A novel method of simultaneous inversion of optical and infrared data was presented by Durech et al. (2012, LPI Contribution No. 1667, id.6118). The new algorithm uses the same convex shape representation as the lightcurve inversion but optimizes all relevant physical parameters simultaneously (including the shape, size, rotation vector, thermal inertia, albedo, surface roughness, etc.), which leads to a better fit to the thermal data and a reliable estimation of model uncertainties. We applied this method to selected asteroids using their optical lightcurves from archives and thermal infrared data observed by the Wide-field Infrared Survey Explorer (WISE) satellite. We will (i) show several examples of how well our model fits both optical and infrared data, (ii) discuss the uncertainty of derived parameters (namely the thermal inertia), (iii) compare results obtained with the two-step approach with those obtained by our method, (iv) discuss the advantages of this simultaneous approach with respect to the classical two-step approach, and (v) advertise the possibility to use this approach to tens of thousands asteroids for which enough WISE and optical data exist.

Density and internal structures are among the most critical characteristics of asteroids, yet these properties are also some of the least known. For distant asteroids (in the Main Belt and beyond), they were, until now, accessible only for some of the largest (>100 km in size) asteroids. Going to smaller and fainter asteroids can revolutionize our understanding by sampling a new regime in physical properties. Here we discuss how asteroid satellites can be observed by ground-based interferometers and the data that can be obtained. This is the most accurate approach for measuring the mass of an asteroid without a spacecraft.

In the frame of the DPAC consortium preparing the Gaia mission, a specific follow-up activity has been set up in order to ensure best scientific return related to solar-system-object (SSO) science. This activity encompasses a system of alerts for newly detected objects provided by CNES, the French data center in charge of the Solar System data processing, and IMCCE, to organize and publish the alerts, and to retrieve the objects astrometry and feed the Minor Planet Center database. We are expecting in particular the detection of new near-Earth objects (NEO) at low solar elongation, or even inner-Earth objects. Owing to its observing mode, the satellite will not be able to monitor these objects after discovery and they could be lost. It is thus important to consolidate and improve their orbital parameters. This is the objective of the SSO ground-based follow-up. Once the objective is reached, it is possible to update the auxiliary database of orbital elements used within the Gaia data reduction pipeline for identifying the known SSOs and to allow Gaia to subsequently identify these objects properly during its mission. In order to reach these goals we have carried out two main activities: -- We have developed a pipeline for processing the Gaia raw data that will be received, and for disseminating only the topocentric data useful for observers in an automatized way -- We have set up a worldwide network of observing stations, the Gaia-FUN-SSO network (shortly described at https://www.imcce.fr/gaia-fun-sso/). At this date, 55 observing sites have registered and many participants have already contributed to several training campaigns for NEO observations. We will describe both activities and we will give preliminary results regarding the Gaia Solar System alerts, depending on the status of the triggering system during this early stage of the mission.

The Herschel MACH-11 (Measurements of 11 Asteroids & Comets with Herschel) Programme has as its prime goal to observe those asteroids & comets which have been or will be visited by spacecraft or those which are being studied with a similar goal in mind. The following near-Earth asteroids (NEAs) form part of the list of targets making up this program and will be addressed in this analysis: - 1999 JU3 (Hayabusa 2 mission target) - 1999 RQ36 (OSIRIS-REx mission target) - 1996 FG3 (Marco-Polo R backup mission target) - (99942) Apophis (Study target)
An additional NEA (not part of the MACH-11 program) will also be reviewed, namely 2005 YU55.
Each target was observed using the PACS Photometer of the Herschel Space Observatory (Pilbratt et al 2010). The extracted fluxes from each observation campaign were fed into a thermophysical model which has been validated against a large database of asteroids including targets of other spacecraft missions. In all cases, radiometric properties of each target have been derived and will be presented, with their impact on already published data being analysed & discussed.

We obtained a dual-band thermal lightcurve of the largest asteroid (1) Ceres with the Herschel Space Observatory on April 23/24, 2013. The measurements were taken with the PACS instrument in the 70- and 160-micron bands in parallel. They span a time interval of 12 hours --- one measurement every hour --- to cover approximately 120 % of the Ceres rotation period of 9.1 hours. Due to the very high stability of the PACS detectors, we were able to detect a rotation-related thermal flux variation of about 1 % (peak-to-peak). We interpret our thermal measurements with a thermophysical model [1] based on a Ceres size and shape model which was derived from HST observations [2], combined with the spin-axis orientation presented in [3], and a rotation period from [4]. We studied the object's thermal properties and investigated the origin of the thermal lightcurve in the context of the available surface albedo map. We will present our results of these high-precision photometric measurements with Herschel-PACS.

We report the detection of water vapour on (1) Ceres, the first unambiguous discovery of water on an object in the asteroid main belt. Most of the water vapour stems from localized regions at low latitude, possibly from surface features known from adaptive-optics observations. We suggest either cometary-type sublimation from the near surface or cryovolcanism as the origin of the waver vapour.
The snowline conventionally divides Solar System objects into dry bodies, ranging out to the main asteroid belt, and icy bodies beyond the belt. Recently, the detection of dust emission from "main-belt comets" and of hydration features and possible water ice absorption on some main-belt asteroids, together with theories of migration of small bodies in the solar system, cast some doubts on the classical picture.
Ceres is thought to be differentiated into an icy core and a silicate mantle and hydrated minerals were found on infrared spectra of its surface. A marginal detection of OH, a photodissociation product of water was reported in 1991, but questioned by later, more sensitive observations. We observed Ceres with the Heterodyne Instrument for the Far Infrared (HIFI) on the Herschel Space Observatory in the context of the MACH 11 guaranteed time program and with a follow-up DDT program. The observations took place in Nov. 2011, Oct. 2012, and March 2013. We searched for the signature of water in the ground state line of ortho-water at 556.936 GHz. After a non-detection in the first observation, an absorption line is clearly visible in all other observations. In March 2013, water is detected in emission as well (at 3 sigma level). The production rate of water on Ceres is a few times 10²⁶ s^-1.
The signal from the water vapour from Ceres was found to be linearly polarized during some of the observations, with the absorption being stronger in the horizontal branch. The measured line-area ratio of up to 2.5 between H and V polarizations is so far unexplained.
The water signal varies on timescales of hours. We interpret this variation as localized sources on Ceres surface rotating into and out of the hemisphere visible for Herschel. The time variability is consistent with those sources being dark features known from ground-based adaptive-optics observations.
The water vapour on Ceres may be either produced by near-surface ice heated by sunlight (cometary activity) or by cryovolcanoes or geysers getting their energy from the Ceres interior. In the first case, the production rate is expected to peak around perihelion, while for volcanic activity the time variations are expected to be more stochastic. The existing observations appear consistent with the cometary hypothesis, but do not allow to clearly distinguish between those possibilities. Upon its arrival at Ceres in 2015, the Dawn spacecraft may provide insight into the sources and mechanisms of water production at Ceres.

Very red featureless asteroids (spectroscopic D-types) are expected to have formed in the outer Solar System far from the Sun. They comprise the majority of asteroids in the Jupiter Trojan population, and are also commonly found in the outer main belt and among Hildas. The first evidence for D-types in the inner and middle parts of the main belt was seen in the Sloan Digital Sky Survey (SDSS).
Here we report follow-up observations of SDSS D-type candidates in the near-infrared. Based on follow up observations of 13 SDSS D-type candidates, we find a ~20% positive confirmation rate. Known inner belt D-types range in diameter from roughly 7 to 30 km. Based on these detections we estimate there are ~100 inner belt D-types with diameters between 2.5 and 20 km. The lower and upper limits for total mass of inner belt D-types is 2 x 10¹⁶ kg to 2 x 10¹⁷ kg which represents 0.01-0.1% of the mass of the inner belt.
The inner belt D-types have albedos at or above the upper end typical for D-types [6] which raises the question as to whether these inner belt bodies represent only a subset of D-types, they have been altered by external factors such as weathering processes, or if they are compositionally distinct from other D-types. All D-types and candidates have diameters less than 30 km, yet there is no obvious parent body in the inner belt. Dynamical models have yet to show how D-types originating from the outer Solar System could arrive at the inner reaches of the main belt under current scenarios of planet formation and subsequent Yarkovsky drift.

Spin and 3-D shape are basic geometrical properties of an asteroid, yet required in understanding some of its most fundamental features, from its density to its sensitiveness to YORP and Yarkovsky non-gravitational effects. Technological advancements have made it possible to obtain highly detailed images of asteroids, yet 3-D shape modeling remains a challenge. Shape inversion is an ill-posed inverse problem as systematic errors, shading effects due to non-convex features, and the limitations of the imaging systems render the direct inversion impossible. Moreover, the image coverage of one observation session is often insufficient for 3-D reconstruction, necessitating the combination of different imaging methods. We will discuss parametric shape representation methods, applicable to all asteroid surfaces, including strongly non-convex and geometrically non-starlike shapes. Additionally, we will demonstrate the usefulness of Fourier transform in shape reconstruction, showing that the frequency domain is a natural setting for shape inversion of image data obtained from generalized projection operators, which include virtually all disk-resolved astronomical observation methods. Finally, we present several examples and applications of our method to range-Doppler radar, adaptive optics, and thermal infrared interferometry.

Each compositional class of asteroid is a relic of the temperature and composition conditions in which it formed. The current distribution reveals the history of the Solar System, and each body acts as a marker of any mixing that occurred since formation. The remnant of a primordial temperature gradient, seen as transition from the S class to C class dominating in different regions of the asteroid belt has been a paradigm for three decades [1-4]. Today, we are armed with major advancements from the past decade that have revolutionized the field of asteroids in areas such as discovery, physical characterization, and dynamical models. A new and more detailed compositional map [5,6] created with data from the Sloan Digital Sky Survey [7] allows us to re-examine compositional trends in the main asteroid belt and what the physical and dynamical implications might be. This talk is related to recent work from DeMeo & Carry 2013, 2014 [5,6] and an upcoming chapter of the "Asteroids IV" book in 2015.

We expect there to have been many bodies in the Main Asteroid Belt (MB) sufficiently heated at the time of solar system formation to allow their interiors to differentiate into an iron core and silicate-rich crust and mantle. Evidence for early solar system differentiation includes the diversity of iron meteorites that imply the existence of over 60 distinct parent bodies (Mittlefehldt et al. 2006). Searches have been performed to identify silicate-rich basaltic crust material (spectral V-type asteroids) in the outer MB have been successful (e.g., Roig et al. 2006, Masi et al. 2008, Moskovitz et al. 2008, Solontoi et al. 2012). The olivine-rich mantles of differentiated asteroids should have produced substantially greater volumes (and therefore substantially greater numbers) of remnant asteroids compared with basaltic and iron samples. Yet olivine-rich asteroids (A-types) are one of the rarest asteroid types (Bus & Binzel 2002, DeMeo et al. 2009). An alternative way to search for differentiated bodies that have been heavily or completely disrupted is to identify these spectral A-type asteroids, characterized by a very wide and deep 1 micron absorption indicative of large amounts (> 80%) of olivine. Burbine et al. (1996) proposed that these asteroids are only found among the largest because most were "battered to bits" due to collisions, so smaller A-types were below our detection limit. Using the Sloan Digital Sky Survey Moving Object Catalog to select A-type asteroid candidates, we have conducted a near-infrared spectral survey of asteroids over 12 nights in the near-infrared in an effort to determine the distribution and abundance of crustal and mantle material across the Main Asteroid Belt (MB). From three decades of asteroid spectral observations only ~10 A-type asteroids have been discovered. In our survey we have detected >20 A-type asteroids thus far throughout the belt, tripling the number of known A-types. We present these spectra and their distribution throughout the MB. We estimate the total mass of mantle material present in the belt today and discuss the implications.

The ESA astrometric mission Gaia has been launched in December 2013. It is currently in its commissioning phase, with the first scientific data expected to be downloaded in June 2014. Gaia has the capability to observe, in addition to about one billion of stars, a large number of solar system objects (SSO). The satellite and telescope will continuously scan the sky during 5 years, providing high precision astrometry and photometry for about 300,000 asteroids (and several tens of planetary satellites and comets), as well as modest imaging for a fraction of them. The nominal limiting magnitude is expected to be V=20, however the end of the commissioning will show the actual performances for the faint targets.

We report the detection of water vapour on (1) Ceres, the first unambiguous discovery of water on an object in the asteroid main belt. Most of the water vapour stems from localized regions at low latitude, possibly from surface features known from adaptive optics observations. We suggest either cometary-type sublimation from the near surface or cryovolcanism as the origin of the waver vapour.

Very red featureless asteroids (spectroscopic D-types) are common among Jupiter Trojans, Hildas, and the outer main belt, and are thought to have formed in the outer solar system. Dynamical models of planetary migration and orbital drift by the Yarkovsky effect predict these D-types could have been transported as close to the sun as the middle main belt, but not closer. We detect D-types in the inner main belt, where they are not expected, through follow-up observations of 13 D-type candidates as determined by SDSS colors. Near-infrared spectroscopic measurements were taken using SpeX on the IRTF. Known inner belt D-types range in diameter from roughly 7 to 30 kilometers. Based on these detections we estimate there are about 100 inner belt D-types with diameters between 2.5 and 20km. The total mass of inner belt D-types is 4x10¹⁶ kg which represents 0.01% of the mass of the inner belt (note Vesta alone accounts for 2/3 of the inner belt mass). Dynamical models have yet to show how D-types could penetrate into the inner reaches of the Main Belt.

We present results of a spectral survey detecting olivine-rich mantle remnants (spectral A-type asteroids) of disrupted differentiated bodies more than doubling the known sample.

With NASA's Dawn Mission now on its way to dwarf-planet Ceres, there is considerable interest in refining that object's size and pole. At the level of a few percent, there has been a discrepancy in the polar and equatorial dimensions of the object, as measured by HST imaging vs. ground-based adaptive optics. To attempt to improve the dimensions and pole, we have analyzed a suite of adaptive optics images that we obtained at the Keck and VLT observatories from 2001 to 2010. We use a new method that we recently developed to combine data from multiple epochs and we attempt to account for limb darkening. We find that Ceres is best modeled as an oblate spheroid with equatorial and polar diameters of 966±10 km and 884±4 km, respectively. Although our equatorial diameter is within 1% of HST results (Thomas et al. 2005, Nature 437, 224-226) the polar dimension is some 3% smaller, more in line with the analysis of a subset of our AO images by Carry et al. (2008, A&A 478, 235-244). Thus, in addition to a more oblate spheroid, we predict that Dawn will find that Ceres shows strong limb darkening when it arrives in 2015. From three methods, all depending on the orientation of Ceres over the nine years of our observations, we determine its spin-vector coordinates to lie within 3° of (287°, +64°) in equatorial EQJ2000 reference frame (346°, +82°] in ECJ2000), in agreement with previous studies, pointing to a small 3° obliquity between the spin and orbital poles.

The distribution of asteroids across the Main Belt has been studied for decades to understand the current compositional distribution and what that tells us about the formation and evolution of our solar system. In this work, we reexamine the architecture of the asteroid belt by determining the bias-corrected distribution of 99.99% of its mass based on compositional information provided by ground-based and space-based measurements. The main belt's most massive classes are C, B, P, V and S in decreasing order. Excluding the four most massive asteroids, (1) Ceres, (2) Pallas, (4) Vesta and (10) Hygiea that heavily skew the values, primitive material (C-, P-types) account for more than half main-belt and Trojan asteroids by mass, most of the remaining mass being in the S-types. All the other classes are minor contributors to the material between Mars and Jupiter. Additionally, we present the taxonomic distribution of asteroids as a function of size. The relative mass contribution of each class changes as a function of size in each region of the Main Belt. We report an updated view of the distribution of asteroid compositions according to distance and size.

(87) Sylvia is the first minor planet known to possess two moons (Marchis et al. Nature 2005). Combining Adaptive Optics data from 8-10m class telescopes, with lightcurve observations and the result of an exceptional stellar occultation on Jan. 6 2013, we report new insights on the dynamical and physical properties of (87) Sylvia. Based on Keck, Gemini and VLT AO observations collected from 2001 to 2011 we derived the mutual orbits of the system which can be fitted by a simple Kepler model (J2=0). From this model, we predicted the relative positions of the moons at the time of this event with an accuracy better than 10 km on the Earth. 50 observers were mobilized along the path of the event and 16 of them reported an occultation, 4 of them by Romulus, the outer moon of Sylvia. A new non-convex shape model of Sylvia's primary was built (Deq = 270 ± 3 km, leading to a density of 1.3±0.1 g.cm^-3

The ESA astrometric mission Gaia, that will be launched in 2013 Q4, has the capability to observe a large number of solar system objects. Gaia will continuously scan the sky during 5 years providing high precision astrometry and photometry as well as modest imaging for about 300,000 asteroids and several tens of planetary satellites and comets down to magnitude V?20. We will present some direct scientific outcome from the astrometry of the bodies in the various classes (NEOs, MBAs, Trojans, Centaurs and TNOs, comets and satellites). This encompass astrometry of moving and resolved body from an essentially 1D signal, and by combining the 5 years data orbit determination and/or improvement, asteroid mass determination, non gravitational forces, local test of general relativity (GR), reference frames linking. We will also present the ground-based support for follow-up in alert of critical object, and touch upon the scientific exploitation for planetary satellites dynamics, stellar occultations and other applications from combination of the ground-based and space-based data.

Amateur contributions to professional publications have increased exponentially over the last decades in the field of Planetary Astronomy. Here we review the different domains of the field in which collaborations between professional and amateur astronomers are effective and regularly lead to scientific publications. We discuss the instruments, detectors, softwares and methodologies typically used by amateur astronomers to collect the scientific data in the different domains of interest.

Asteroid satellites help determine mass, density, and composition. LINC-NIRVANA will yield a factor of 3 improvement in the limiting separation for detections.

With it being approximately 2000 x 1600 x 1000 km in size, (136108) Haumea's extreme elongation makes it unique among known dwarf planets. The shape of this fascinating Kuiper Belt Object (KBO) is the result of a rotational deformation due to its extremely short 3.9-hour rotation period (Rabinowitz et al. 2006) which could be explained by a past dramatic collision (Brown et al. 2007 ; Ragozzine & Brown 2007; Snodgrass et al. 2010). Although a high bulk density estimated at a range of 2.6 to 3.3 g.cm-3 (Rabinowitz et al. 2006) suggests a more rocky composition than other KBOs, Haumea and its satellites are considered by a crystalline water-ice multiple system (Dumas et al. 2011). Moreover, Haumea has become the second Kuiper Belt Object after Pluto to show observable signs of surface features. Indeed, a region darker and redder than average on the surface of Haumea has been identified (Lacerda, 2010). In this contribution, we present Spectro-Imaging observations of Haumea obtained in the Near Infra- Red [1.6 to 2.4 ?m] with the integral-field spectrograph SINFONI mounted on UT4 at the ESO Very Large Telescope. We present some results combining data from several epochs.

We report AO imaging observations from Keck Observatory of NEA 2005 YU55 during the night of its close approach to Earth on 2011 Nov 9 UT. Our goals were to acquire estimates of the size, shape, and pole direction as well as search for satellites.

From Adaptive Optics (AO) images of (9) Metis at 14 epochs over 2008 December 8 and 9 at Gemini North, triaxial ellipsoid diameters of 218x175x112 km are derived with fitting uncertainties of 3x3x47 km. However, by including just two more AO images from Keck-II in June and August of 2003 in a global fit, the fitting uncertainty of the small axis drops by more than a third because of the lower sub-Earth latitude afforded in 2003 (-28°) compared to 2008 (+47°), and the triaxial ellipsoid diameters become 218x175x129 km with fitting uncertainties of 3x3x14 km. We have estimated the systematic uncertainty of our method to be 4.1, 2.7, and 3.8%, respectively, for the three diameters. These values were recently derived (Drummond et al., in prep) from a comparison of KOALA (Carry et al, Planetary and Space Science 66, 200-212) and our triaxial ellipsoid analysis of four asteroids. Quadratically adding this systematic error with the fitting error, the total uncertainty for Metis becomes 9x5x15 km. Concurrently, we find an EQJ2000 rotational pole at ($alpha;,$delta;)=(185°, +19°) or in ecliptic coordinates, (λ,β)=(176°, +20° in ECJ2000).

Each compositional class of asteroid is a relic of the temperature and composition conditions in which it formed. The current distribution reveals the history of the Solar System, and each body acts as a marker of any mixing that occurred since formation. The remnant of a primordial temperature gradient, seen as transition from the S class to C class dominating in different regions of the asteroid belt has been a paradigm for three decades (Gradie & Tedesco 1982, Science, 216, 1405). In this work, we reexamine the architecture of the asteroid belt by determining the bias-corrected distribution of 99.99% of its mass based on compositional information provided by ground-based and space-based measurements. We report an updated view of the distribution of asteroid compositions. This material is based upon work supported by the National Science Foundation under Grant No. 0907766.

In recent years, many efforts have been undertaken to extract the astrometry, photometry, and colors of Solar System Small Bodies from large surveys and widefield camera, such as the SDSS Moving Object Catalog or EuroNear. Since 2006, the IMCCE provides a service, called SkyBoT, that list all the Solar System Objects in a given field of view for a given epoch. Such a tool is of high interest for any data mining purpose of large archives. We will present an extension of SkyBoT from ground-based to space-based geometries. As a demonstration, we will present our search for serendipitously observed asteroids in the data archive of the OSIRIS instrument on-board the ESA Rosetta mission.

Asteroid (1) Ceres may contain substantial amounts of water ice in its crust. Even a small fraction of water ice on Ceres' surface would produce measurable amount of water vapour. Past searches for a water exosphere through observations of the dissociation product OH led to inconclusive results. We are using the Heterodyne Instrument for the Far Infrared (HIFI) onboard Herschel to search for water vapour emission and absorption. A first observation close to Ceres' aphelion did not result in water detection, leading to an upper limit of about 1026 s-1. A second observation closer to perihelion will be performed end of 2012 or early 2013. In addition, we will report on the search for absorption features from water vapour and organic molecules in spectra taken with Herschel's Photodetector Array Camera and Spectrometer (PACS).

The asteroid (21) Lutetia has been observed by several instruments aboard ESA's ROSETTA spacecraft on July 10, 2010. The OSIRIS imaging system allowed the reconstruction of the topography of its surface. A number of intriguing features appeared on the images and/or on the topographic models: boulders, landslides, craters with various profiles, among others. The combination of these data with light curves and adaptive optics profiles allowed to retrieve the global shape of the asteroid, which yielded an estimate of its volume. Combined with the accurate mass determination from the radio science RSI instrument, a very high density of 3.4 g/cm^{3} was obtained.

Nowadays more than 200 asteroids have been identified as multiple. These systems are found all over the Solar System (Near-Earth, Main-Belt and Trojan asteroids, Trans-Neptunian objects). The study of the stability of these multiple systems is quite complex, because of their irregular shapes, and requires a full body-full body approach. More specifically, in the case of satellites of asteroids (when one of the body is much greater than the others), the shape of the main object has a major influence on the motion of the small bodies. This perturbation can be more important than the perturbation of the Sun or of the planets. The introduction of this shape effect in a numerical integration requires the knowledge of many coefficients of the spherical harmonic expansion of the gravitational potential; their computation is performed using the software SHTOOLS and a shape model. Once the coefficients of the gravitational potential are determined, the dynamics of the asteroid satellites is described thanks to the software NIMASTEP, for the full short periodic motion, and, thanks to a home-made program (developed by J. Frouard), for the averaged long periodic motion. Two applications are presented here: the search for mean-motion, gravitational and secular resonances in the triple system (87) Sylvia, explaining its present and future configuration, and the validation of orbit for the binary system (41) Daphne.

Ceres is believed to possess an ice-rich crust, opening up the possibility of an exosphere around it. We searched for water vapour around Ceres with Herschel/HIFI. No line signal was detected, suggesting a very low surface ice coverage on Ceres.

We report on our efforts to search for faint satellites of Pluto using Keck 2 adaptive optics (AO). Last year, using HST, Showalter et al. 2011 (IAUC 9221) discovered a new, faint satellite ("P4") around Pluto, demonstrating that Pluto is even richer with orbiting material than was thought previously. That discovery led to speculations that these small satellites could be a source of debris (from random impacts) that could pose a hazard to the New Horizons (NH) spacecraft during its 2015 Pluto flyby. The ejecta would form a cloud around Pluto. The NH project began an aggressive program of HST- and ground-based studies to identify additional as-yet-unseen satellites or debris rings in the system. Only several days into their campaign, a 5th satellite "P5" was discovered with HST (Showalter et al. 2012, IAUC 9253). The output of these studies will be used to plan a contingency ("safe-haven") trajectory through the system. The Keck observations support and complement the new HST observations. Real objects in the HST images may be hidden by bad pixels or diffraction spikes, and Keck may have advantages in some regions of parameter space, such as interior to Charon. r Observing in a near-IR band, the Keck imaging provides additional constraints on the objects, but this makes the observations particularly challenging because of the sky brightness. We have made an effort to optimize the Keck AO observations. Near-IR imaging requires tradeoffs between sky brightness and post-correction Strehl. Expectations and our early results favor H-band in typical conditions. Contrary to prior experience with V 14 targets, we find Laser-Guide-Star AO correction to be far more effective than using Pluto as the wavefront source (NGS). We have achieved imaging that could detect satellites smaller than Nix at good S/N, even in a relatively short (15 min) span.

We consider inversion methods for shape reconstruction with complementary data sources. We present a generally applicable shape support for non-starlike shapes. New models of Kleopatra and Hermione are presented.

We will present a new general method that combines asteroid photometry in the optical with thermal IR radiometry to derive physical models of asteroids. The method includes both data types at once and optimizes all the relevant physical parameters.

The astrometry mission Gaia of the European Space Agency (ESA) will scan the entire sky several times over 5 years, down to a visual apparent magnitude of 20. Apart for its primary targets, the stars, that will be mapped during the course of the mission, Gaia is expected to observe more than 300,000 asteroids (Mignard et al., 2007). Although our census of asteroids is about complete at a such magnitude limit, the location of Gaia at L2 may allow the detection of yet-unknown near-Earth asteroids (NEAs). The pre-defined and smooth scanning law of Gaia, however, is not meant for pointed or follow-up observations. A ground-based network of observers has therefore been set up, the Follow-Up Network for the Solar System Objects (FUN SSO), centered around a central node (the DU459 of the Gaia Data Processing and Analysis Consortium, the DPAC). The aim of this network is to quickly observe from the ground the NEAs newly discovered by Gaia to secure an accurate orbit.
Following the description of the overall organization and status of the network presented by Thuillot et al. (2012), we present here the details of its central node host at the Institute for Celestial Mechanics and Ephemeris Computation (IMCCE) in Paris, France. The role of the node will be, upon detection by Gaia of a target judged as interesting for or requiring a follow-up, suitable for observations by the network, to release calls for observations, and to provide support to the observers. We describe in particular the current implementation and development of the system that will be used by the node and of the various solutions envisaged to interact with the network of observers.

During the Gaia mission, Solar System Object alerts will be triggered toward the ground. We have set up the Gaia-FUN-SSO network in order to coordinate fast reaction for the observation of these targets. In this article, we describe this network at the present stage, its recent activity for training campaigns of observation, and its next activity. We discuss also some points related to this organization and the strategy of observation.

In this contribution, we report spectro-imaging observations of all three components of the Haumea system performed in 2007 with the ESO-VLT nearinfrared integral-field spectrograph SINFONI and its Laser Guide Star Facility [6]. Our data and related compositional modeling show that the surface of the outer satellite Hiiaka is mostly coated with crystalline water ice, as in the case of the central body Haumea [7], [8], whose surface appears to be made of large grains of water ice, almost entirely in its crystalline form. We also discuss possible sources of heat to maintain water in its crystalline state. Finally, we report on the preliminary analysis of a similar highcontrast spectroscopic data set obtained this year on Haumea, but for a different rotational phase than our 2007 observations.

Prior to and around ESA Rosetta's flyby of (21) Lutetia, a collaborative observation campaign using another ESA satellite, the ESA Herschel Space Observatory, was performed whereby Herschel's two photometers observed the asteroid in the far infrared, at wavelengths not covered by the Rosetta instruments. The Herschel observations, fed into a thermophysical model (TPM) using as input a flyby image based shape model (built upon Rosetta OSIRIS instrument observations) were further correlated with ~70 multi-wavelength (IRAS, ISOVISIR, IRTF, Akari, ESO-TIMMI2, Spitzer-IRAC) observations of Lutetia. We confirm the albedo measured by Rosetta and derive a "true" H-mag value based upon the cross-sections of the asteroid observed from all aspect angles. From our measurements we find that (21) Lutetia has an extremely low thermal inertia as well as a very low surface temperature. In addition, we have been able to identify a hill/crater surface feature located on the asteroids southern region not observed by Rosetta. We conclude that only through the merging of in-situ flyby based observations and remote sensing observations can a true global picture be obtained of this peculiar asteroid.

The triaxial ellipsoid dimensions and rotational pole of the large asteroid (19) Fortuna were found from only three nights of adaptive optics images in November 2009 at the 8 meter Gemini North telescope at &lambda$ = 2.15 μm. The dimensions and pole, as well as images, are supported by the model derived from lightcurve inversions and stellar occultations. Fortuna should perhaps be considered a candidate for a Standard Triaxial Ellipsoid.

A crater structure of about 21 km diameter is the most prominent feature on the hemisphere of Asteroid (21) Lutetia that was observed by the OSIRIS cameras during the flyby of the Rosetta spacecraft. It shows the presence of landslides, numerous large boulders, and the largest colour variations found on the surface of the asteroid. We present evidence that it is the youngest large geological feature seen by Rosetta, and we show that there are variations in composition or size of its surface material.

We describe our on-going observing program to determine the physical properties of asteroids from groundbased facilities. We combine disk-resolved images from adaptive optics, optical lightcurves, and stellar occultations to put tighter constraints on the spin, 3-D shape, and size of asteroids. We will discuss the relevance of the determination of physical properties to help understand the asteroid population (e.g., density, composition, and non-gravitational forces). We will then briefly describe our multi-data inversion algorithm KOALA (Carry et al. 2010a, Kaasalainen 2011, see also Kaasalainen et al., same meeting), which allows the determination of certain physical properties of an asteroid from the combination of different techniques of observation. A comparison of results obtained with KOALA on asteroid (21) Lutetia, prior to the ESA Rosetta flyby, with the high spatial resolution images returned from that f

Ephemerides of solar system bodies are needed for many applications such as operation of the telescopes, prediction of instruments performance, planing of observation campaigns, reduction of astrometric, photometric, or spectrometric data, analysis of space probe images, etc. Dynamical and physical studies of the small bodies of the solar system based on stellar occultation, astrometry, photometry, radiometry and high angular resolution observations also show the need of having good ephemerides over mid-term time scales. In this paper we give a presentation of Miriade, the new version of the IMCCE ephemeris service on the web. It is a major upgrade from the previous services available at IMCCE providing positional and physical ephemerides of planets and small bodies (asteroids, comets, satellites) of the solar system as well as some physical data. Miriade is part of the more general IMCCE-VO solar system portal in the Virtual Observatory (VO) framework, making use of a name resolver for the solar system bodies, and providing many functions.

In a campaign to study the Rosetta mission target, asteroid (21) Lutetia, we obtained 81 images on December 2, 2008, at 2.12 microns with adaptive optics (AO) on the Keck-II 10 m telescope. From these nearly consecutive images obtained over a quarter of rotation, we have determined the asteroid's triaxial ellipsoid diameters to be 132x101x76 km, with formal uncertainties of 1 km for the equatorial dimensions, and 31 km for the shortest axis. This latter uncertainty occurs because the observations were made at the relatively high sub-Earth latitude of -69 degrees. From these observations we determine that Lutetia's pole lies at 2000.0 coordinates of RA=48, Dec=+9, or Ecliptic coordinates of [49;-8], with a formal uncertainty radius of 3 deg. (The other possible pole is eliminated by considering its lightcurve history.) The rotational pole derived for the lightcurve inversion model (available at http://astro.troja.mff.cuni.cz/ projects/asteroids3D/web.php), is only 5 deg from ours, but comparing our images to the lightcurve inversion model we find that Lutetia is more pointed than the model. Our technique of deriving the dimensions of asteroids from AO images has been calibrated against Pluto and 4 satellites of Saturn with precise diameters, and we find that any systematic errors can be no more than 1-3%.
We acknowledge the assistance of other team members Christophe Dumas (ESO), Peter Tamblyn (SwRI), and Clark Chapman (SwRI). We also thank Hal Weaver (JHU/APL) as the lead for our collaboration with the Rosetta mission. We are grateful for telescope time made available to us by S. Kulkarni and M. Busch (Cal Tech) for a portion of our overall Lutetia effort. We also thank our collaborators on Team Keck, the Keck science staff, for making possible some of the Lutetia observations and for their participation. Additional Lutetia observations were acquired at Gemini North under NOAO time allocation.

We report an unexpected variability among mid-infrared spectra (IRTF and Spitzer data) of 8 S-type asteroids for which all other remote sensing interpretations (e.g. VNIR spectroscopy, albedo) yield similar compositions. Compositional modelling making use of their mid-IR spectra only yields surprising alternative conclusions: 1) these objects are not "compositionally similar" as the inferred abundances of their main surface minerals (olivine and pyroxene) differ from one another by 35%. 2) Carbonaceous chondrite and ordinary chondrite meteorites provide an equally good match to each asteroid spectrum.
Following the laboratory work of Ramsey & Christensen (1998), we interpret this variability to be physically caused by differences in surface particle size. Mid-IR measurements of surfaces having particle sizes that are large compared to the 8-13 micron wavelength range yield compositional interpretations that remain compatible with other types of remote sensing. Surfaces having grain sizes near or below the 8-13 micron wavelength scale of mid-IR measurements yield divergent compositional interpretations. Thus for asteroids, we find mid-infrared measurements are a powerful tool for inter-comparison of surface properties for objects of known compositions. Those yielding compatible mid-IR compositional interpretations likely have large particle sizes on their surfaces. Divergent compositional interpretations are more likely indicative of surfaces dominated by particles at or below the 8-13 micron scale of mid-IR radiation. Thus for mid-IR measurements of objects whose surface properties are not known, a reliable compositional interpretation based solely on linear deconvolution of mid-IR measurements with existing spectral libraries is problematic.

We report results from recent high-angular-resolution observations of asteroids using adaptive optics (AO) on large telescopes.

The ESA cornerstone mission Gaia, to be launched during end-2011, will observe ~ 250,000 small bodies. These are mostly main belt asteroids, but also Near-Earth objects, Trojans, and a few comets, or planetary satellites. The scientific harvest that Gaia will provide - given the high astrometric accuracy (at sub-milli-arcsec level), valuable photometric measurements (at milli-mag level), and moderate imaging (about 2,000 objects will be resolved) - will have a major impact on our knowledge of this population in terms of composition, formation and evolution tep{mignard07}. There are nevertheless some intrinsic limitations in particular due to the unavoidable limited duration of the mission (5 years), the peculiar observing strategy that is not optimised to the observation of solar system objects, and last, the limited imaging possibilities. We can thus identify two kind of complementary data and ground-based observations, whether they are part of the Gaia Data Processing and Analysis Consortium (DPAC), or not, but provide a strong leverage to the Gaia science.
We discuss different aspects of additional observations from ground (yet not exclusively) either in preparation to the Gaia mission, in alert during the mission, or after the mission as additional complementary information. Observations of a set of well defined and selected targets, with different telescopes and instrumentation, will increase the scientific output in three particular and important topics: mass of asteroids, their bulk density and possible link to their taxonomy, and non-gravitational forces.

Near-symmetric binaries - i.e., binaries with roughly samesized partners - appear to dominate the known population of binaries in the Kuiper-belt. Herein the mass- and sizeratio distributions, as well the resulting orbit properties, of Kuiper-belt binaries predicted by the chaos-assisted capture formation model are presented.

As part of our ongoing programs to use adaptive optics (AO) to study asteroids for size, shape, and presence of satellites, we observed asteroid (41) Daphne during its recent close (1.05 AU) opposition. In March 2008, we discovered a small satellite to Daphne at Keck (Conrad et al. 2008, IAUC 8939; Merline et al. 2008, ACM 2008, #8370). Follow up observations at Keck and VLT allowed us to refine the orbit. The unusually short period of the satellite (~1.1 day) and the estimated size (239x183x153 km) from our observations lead to a density near 2.0 g/cc. This is significantly higher than most other large C-types with densities determined from presence of a moon (Merline et al. 2002, Asteroids III, 289). Because of this surprising density, and because we expect to derive an exceptionally accurate volume from our data, we are placing special emphasis on our size and shape determinations. One of the peculiarities is that this object is highly irregular in shape. We demonstrate several methods of determining the volume, including triaxial ellipsoid fits, detailed shape modeling, and improving estimates by using existing lightcurve information (e.g., from Kaasalainen et al.).

As part of our study of resolved asteroids using adaptive optics (AO) on large telescopes (>8; m), we have identified several that can serve as Standard Triaxial Ellipsoid Asteroids (STEAs), suitable for radar and thermo-physical calibration. These objects are modeled well as triaxial ellipsoids, having: 1) small uncertainties on their three dimensions as determined with AO; 2) rotational poles well determined from both lightcurves and AO; and 3) good sidereal periods from lightcurves. Although AO allows the opportunity to find an asteroid's dimensions and rotational pole in one night, we have developed a method to combine AO observations from different oppositions to pool into a global solution. The apparent orientation and sizes of STEAs can be predicted to within a few degrees and a few km over decades. Currently, we consider 511 Davida, 52 Europa, 2 Pallas, and 15 Eunomia as STEAs. Asteroids that are not well modeled as ellipsoids, clearly showing departures from ellipsoid figures in AO images, include 129 Antigone and 41 Daphne. We will show movies of images and models of these asteroids.

We present imaging data on three asteroids, using adaptive optics and having high spatial and rotational resolution. The resulting shapes can be compared with previous shape models derived from inversion of lightcurve data, and the agreement is generally good.

Introduction: Ephemerides of solar system bodies are most needed in many applications. They are useful to the astronomer to prepare his observations proposal, for accurate thermal modeling, or in analyzing observational data, also for predicting instruments performances of moving and extended objects, etc. Since the pioneering work of Russel it is well known that light-curve of asteroids encompass information on their shape, making them more than only point-like source. And since then, space-probes during their fly-by to asteroids revealed all complex aspects of their macroscopic scale and surface features.
SSODNetWe have developed at the IMCCE a service, named Solar System Object Database NETwork, that offers many possibilities, among which: a name resolver for small bodies of the solar system (and planetary bodies); a data node with a search engine that offers easy inter-connection of various worldwide database; and a computing node for generating position ephemerides as well as ephemerides for the physical observations. This node is similar to the famous JPL Horizons, but with some fundamental technical aspects allowing different use though generic web-service and Virtual Observatory protocol.
Physical ephemerides: The service offers in particular some original features for the computation of asteroids physical ephemerides taking into account their spin and shape models made available from e.g. lightcurve inversion and/or high resolution imaging from optical telescopes, and radar observations. Also different visualizations and data-format outputs are available for uploading and directly through a web-service. For instance one can generate a fits file showing the orientation, brightness distribution, size, etc, that can be used for further convolution with an instrument PSF or transfer function as well as the Aladin system based at CDS. To these one can also add an radial velocity map. In future developments we will include albedo and thermal maps, and comets models. A synthetic database for general studies of the Gaia mission is also in construction.

Introduction. We report the discovery of a small satellite to large C-type asteroid (41) Daphne, using adaptive optics on Keck II. The satellite appears to have the most extreme mass ratio (10⁶) of any binary known. It is also in a particularly close orbit for this class of binary. We consider how difficult is such a detection for large asteroids in the Main Belt, and what consequences it may have for the main-belt binary population and frequency. Because these observations were taken with the intention of not only a deep satellite search, but also rotationally resolved imaging of the primary, we are able to also determine accurately the shape, size, and pole position of the primary. The resulting volume estimate, coupled with the mass from the satellite orbit, will allows us to determine an exceptionally accurate density for this object.
Background. This was a combined effort of two programs, one to determine the shape, sizes, and poles of large main-belt asteroids and one to search for companions to main-belt asteroids. Our main objective in the particular run was to acquire good sizes and shapes for asteroids already known to have companions, and thus improve the volume and hence the densities. Improved size permits improved estimates of albedo, in turn allowing better interpretation of surface composition. If we have a good estimate of the mass, e.g. from the presence of a satellite, uncertainty in an asteroid's volume is the overwhelming uncertainty in attempts to derive its density. Of course, density is the single most critical observable having a bearing on bulk composition, porosity, and internal structure. We can also achieve good surface maps if the objects is large enough, e.g. for our observations of Ceres.
Observations. Our observations were made with the Keck II adaptive-optics imaging system NIRC2/AO on 2008 Mar 28 UT. At this time, asteroid (41) Daphne was approximately 1.09 AU from Earth, and had an angular size of about 0.22". The presents the most favorable size until the year 2031. A small satellite was discovered very close to the primary. The pair was tracked for over 3 hours, resulting in a surprisingly long (0.3") orbital track of the satellite.
Characteristics. Because this discovery was made only a few days before the deadline for this abstract, we have only been able to make preliminary estimates of the system parameters. From the single arc of the orbit, we had at first estimate a semi-major axis of about 443 km, but revised estimates put it at closer to 405 km. The orbital period estimate on our first report was 1.6 days, but this may be revised downward. The most unsual aspect is that this object appears to have the most extreme size ratio of any known binary. The brightness difference of the pair is about 10 magnitudes, giving a size of less than 2 km, and a mass ratio of about 1 million, significantly exceeding typical binaries. In addition, for this class of binary (large main-belt asteroid, with small secondary), undoubted produced via the SMAT (Smashed Asteroid Target) mechanism of Durda et al. (2004), it is also the closest known pair (5.5 primary radii, while most known are at about 10).
Discussion. Such objects may be common, but undetected. With a very high eccentricity, this main-belt object was exceptionally close during these observations. It is possible that many more such close, small satellites exist, and indeed with a typical size distribution and the collision results of Durda et al. (2004), one might expect many more. This may affect the previously claimed binary frequency for the larger main belt objects, which is much lower than in other populations. In addition, some benefit has been gained by the substantially improved AO system at Keck, providing higher Strehl and contrast, allowing us to detect such faint satelletes close to a bright object.

The dwarf-planet (IAU 2006) Ceres, whose mass represents 30 to 40% of the Main Belt, was discovered in 1801 by the Italian astronomer Giuseppe Piazzi. Ceres possesses several intriguing physical characteristics. Among them, a mean density estimated to be near 2.1 g.cm^-3, suggests that the shape of Ceres is the result of a rocky core surrounded by an ice-rich mantle.
A large number of multi-wavelengths observations of Ceres' surface have been carried out in the past years in order to investigate the presence of ices. Thus, some near infrared spectra have been found compatible with the presence of water ice in some regions of Ceres' surface.
Moreover, long-exposure IUE spectra of the region around the limbs of Ceres have been conducted by A'Hearn & Feldman (1992) to explore the possibility that OH resulting from the photodissociation of atmospheric water vapor might escape. They reported the detection of OH above the northern limb of Ceres after perihelion while no evidence of this radical has been found off the southern hemisphere before perihelion.
High resolution spectra were acquired with the Ultraviolet and Visual Echelle Spectrograph (UVES) of the ESO VLT under very good seeing, low airmass (~1.3) and photometric weather. The slit was placed within a few arcseconds off both Ceres' poles to search for the 309 nm OH emission lines which would reveal water escaping from the dwarf planet.
After data reduction with the UVES ESO pipeline and the subtraction of a solar spectrum in order to remove the contamination from sunlight reflected by Ceres within the slit no OH emission line is detected on both northern or southern poles. We will present our observations which permit to derive an upper limit for the OH quantity along the line of sight, as well as for the water production rate of Ceres. Because our observations were conducted with a combination telescope+instrument more sensitive than IUE they contradict the positive detection published by A'Hearn & Feldman. We will discuss the possible reasons for this contradictory result.

Introduction: We present imaging data on 4 larger asteroids, taken with adaptive optics (AO) on large telescopes, with high spatial and rotational resolution. The resulting shapes can be compared with previous shape models derived from inversion of lightcurve data, and the agreement is generally good. The orbit of a satellite discovered orbiting one of these, taken together with volume estimates determined from shape measurements, will yield an exceptionally accurate density for that object.
Resolved Asteroid Program: The physical and statistical study of asteroids requires accurate knowledge of their shape, size, and pole position. Improved size permits improved estimates of albedo, in turn allowing better interpretation of surface composition. In those cases where we have an estimate of the mass, e.g. from the presence of a satellite, uncertainty in an asteroid's volume is the overwhelming uncertainty in attempts to derive its density. Of course, density is the single most critical observable having a bearing on bulk composition, porosity, and internal structure.
Direct, accurate, measurements of asteroid shapes, sizes, and poles are now possible for larger asteroids, which can be well resolved using AO on large ground-based telescopes.

Introduction Asteroid 2 Pallas is the third largest asteroid and until very recently, its physical properties were only loosely constrained. We developed a tool allowing us to combine asteroid shapes measured from adaptive optics (AO) images with light-curves (LC) inversion techniques. LC inversion brings long-term constrains on asteroid spin axis and 3-D shape, without providing absolute measure of its size, nor any surface information. On the other hand, high angular-resolution images provide a direct measurement of an asteroid shape and absolute size, as well as albedo information, but require good rotational phase sampling to derive pole and shape solutions.
Observations We thus compiled near-infrared, high angular-resolution images, with equivalent spatial resolution of about 60 km, obtained within six observation programs conducted at the Keck II Observatory (2) and the ESO Very Large Telescope (4) between 2003 and 2007. The observations span a range of sub-Earth latitudes and longitudes on the asteroid, providing constraints on Pallas' shape from different observing geometries.
Spin, Size and 3-D Shape From LC/AO combined analysis, we removed the ambiguity of the pole solution resulting from the LC only observations. We determined that the coordinates of Pallas' spin vector are within 5 deg of (λ=35°, β=-12°) in ECJ2000.0. We also derived a 3-D model (2038 facets - 276 x 266 x 243 km ± 10 km) rendering Pallas' shape. Such a model allows refined volume measurement. Considering Pallas' mass measurement distribution, its density (2.8 to 5.4 g.cm^-3) is now limited by the mass uncertainty. Pallas' tri-axial values found here are smaller (but consistent) with HST measurements, implying a higher density. We also detected a large, flat surface feature, which may have been created by the impact that formed the Pallas family.
Surface Mapping We produced near-infrared broad-band albedo maps of Pallas' surface. These maps, covering 40%, 40% and 70% of Pallas' surface in J, H and K-band respectively, reveal albedo variations of nearly 10% across its surface.

Introduction: Asteroid (4) Vesta, target of NASA's Dawn mission, is the only known asteroid with a possibly differentiated internal structure. Geological diversity across Vesta's surface has been first reported from Earth-based disk-integrated spectrophotometry; and HST imagery revealed strong albedo variations across its surface, whose origin has not yet been determined. Ion irradiation experiments on Eucrite meteorite have shown that, if solar wind ions do reach the surface of Vesta, its reflectance spectrum should be much redder and its albedo lower. Thus, the similar albedo and NIR reflectance spectrum displayed by Vesta and the HED meteorites reveals Vesta's surface to be either (a) free from heavy space weathering, or (b) continuously refreshed. Both processes have been discussed: the action of local magnetic field (with a required strength at the surface of only ~0.2 μT) has been proposed to explain Vesta shielding from solar wind ions (space weathering), and regolith activity will bring fresh material on surface. Regolith processes can be triggered by global seismic activities (from the giant crater relaxation), or the fall of small-sized debris (~1m) launched from the impact basin and remained in Vesta's gravitational influence.
Observations: We observed Vesta over the 1.1-2.4 μm range during the Science Verification program of SINFONI, the ESO integral-field spectrograph mounted on Cassegrain focus of UT4 at VLT. The observations were obtained in August and October 2004, under good atmospherical conditions, while the asteroid was fully resolved by the system: SINFONI provides a spetral resolution of ~1500 over the range and the AO correction provided a resolution element of about 80 milli-arcsec at 2 micron, corresponding to ~95 km on Vesta.
Surface Analysis: We will present the results inferred from near-infrared wavelength: 1. We compared Vesta's spectra to those of laboratory measured HED meteorites and Augite minerals (clinopyroxene) catalogued in the RELAB database in order to investigate Vesta's pyroxene composition: no clinopyroxene-rich area was detected, and Vesta's overall spectrum is consistent with howardite meteorites. 2. We mapped the distribution of spectral slope and compared it to the albedo distribution obtained from HST to test the magnetic field hypothesis, although the definitive answer will come from NASA Dawn mission.

The impact of a 10-meter telescope on solar-system science began in 1994 when comet Shoemaker-Levy 9 collided with Jupiter. Shortly after Keck's observation of this event, the advent of adaptive optics ushered in an explosion of solar-system observation opportunities, including volcanoes on Io, binary asteroids, rings of outer planets, clouds on Titan, shapes of main belt asteroids, imaging near-Earth asteroids, and the study of larger-than-Pluto Kuiper Belt Objects. Seeing limited (non-AO) observations also continue, including the color characterization of Kuiper Belt Objects, and, more recently, measuring the post-impact chemical abundances of Comet 9P/Tempel 1. The continuing discoveries of planets around other stars, one of Keck's greatest achievements, stands as another example of non-AO science which, although not strictly classified as solar-system science, has major implications for understanding our own solar system.
As we enter the next phase of adaptive optics capability, which for Keck includes a new wavefront controller with a limiting magnitude of 14.5, and a laser guide-star system with a limiting magnitude of 18, new solar-system discovery opportunities are within our grasp. While meeting the technical challenges of these new technologies, ground-based observing faces the related challenge of scheduling telescope time to meet the phase coverage requirements and ability to react to time-critical events required for efficient exploration of the solar-system from the ground.
We review the last 10 years of discovery, and discuss the opportunities and challenges of future technologies and scheduling strategies. In addition to this overview, we also provide specifics of recent work by the authors, including characterization of asteroid (511) Davida's physical properties.

While disk-integrated photometry is the main source of information on most asteroids, adaptive optics can provide some disk-resolved data on many larger (main-belt) asteroids. Asteroid models from lightcurve inversion agree well with the obtained AO images (Marchis et al. 2006, Icarus 185,39), but even more detailed models can be obtained by combining the two sources in inversion. In addition to giving more detail to existing models, the approach can also be used to obtain models of asteroids for which the photometric data are yet insufficient alone. This also helps to calibrate the inversion and deconvolution processes related to the separate sources; e.g., whether features apparently revealed by AO post-processing are real or artificial. We present some examples and discuss the resolution level of topographic detail in the resulting models. Hundreds of asteroids can be mapped in this way in the near future.

We imaged Pallas at high-angular resolution in the J, H and K near-infrared bands using adaptive-optics-equipped cameras at the Keck II and ESO VLT observatories during its 2003 and 2005 oppositions (angular diameter of 0.44 and 0.57 arcsec respectively).
The J-, H- and K-band theoretical resolution element of 28, 37 and 45 km respectively on Pallas' surface were restored by image deconvolution [MISTRAL, Conan et al., 2000]. The very high spatial resolution of the images (~10 resolution elements across the diameter in K) allowed us to extract the edge contour of the asteroid from the individual images using a wavelet analysis and to model its size (276 x 256 x 248 km, ± 10 km).
From comparison between our AO-measured edges and previous lightcurve inversion results [Torppa et al., 2003], we were able to refine Pallas' shape model as well as the solution for its spin vector coordinates (Ecliptic J2000.0 λ=34 ± 5° and β=-11 ± 5°).
We will present the results of our analysis, including the first near-infrared maps of Pallas revealing albedo variations of 4 percent across its surface.

Adaptive optics NIRC2 images of asteroid 1 Ceres have been obtained at Keck Observatory on Sep. 22 and 28, 2002 at phase angle of 7° and 5° respectively. Their optimal spatial resolution was restored using the Mistral deconvolution algorithm [Conan and al., ESO Messenger 2000]. Analysis of our set of deconvolved images allowed us to determine the direction of the spin axis (α=289±-5°, δ=69±5°), which is in agreement with previous study [Thomas et al., Nature 2005], and to produce J/H/K -band high-spatial resolution maps covering 80% of Ceres surface. These first near-infrared maps reveal several albedo features whose intensity variation is of the order of ±6% with respect to the mean surface albedo. The finest details visible on the surface of Ceres are about 40km wide and the largest surface feature sustains a diameter of about 160km. We will present the results of our analysis, including the multi-color near-infrared maps and their reprojection onto a 3-D model of Ceres.

We recently started a program of observations of small solar system bodies using SINFONI, the new [1.0-2.5] μm near-infrared integral-field adaptive-optics-equipped spectrograph installed at the Cassegrain focus of the Yepun 8m telescope at the ESO-Paranal observatory. In this poster we will present our first results obtained on the surface of Pluto's satellite Charon and the large main-belt asteroid 4 Vesta. A separate presentation given at this DPS meeting by Merlin et al. will cover the results obtained on the large Trans-Neptunians Objects 2003 UB313 and 2003 EL61.
High-SNR reflectance spectra (R~1500) of Charon were obtained in 2005 across the H-K spectral bands for three separate orbital positions of the satellite corresponding to intermediate elongations from Pluto (~0.6"). Combined with the published HST-NICMOS results, these data confirmed that the 2.21 μm absorption band attributed to ammonia hydrate is present over the entire surface of Charon. We will present the complete analysis of our spectral data using Hapke models for bi-directional reflectance of solid ices.
We also observed the differentiated asteroid 4 Vesta with SINFONI across the J and H+K bands (R~3000 and 1500 respectively) at various rotational phases in order to map the distribution of minerals on its surface. The observations were obtained in August and October 2004, while the asteroid displayed an aspect angle close to 0°, and Vesta (angular diameter 0.5") was fully resolved by the system. The 3-D spectroscopic capabilities of SINFONI, combined with the availability of an adaptive optics mode, are perfectly adapted to carryout a detailed mineralogical study of the surface of small solar system bodies. We will present the results of mapping the variations in the strength and shape of the pyroxene and olivine bands across the surface of Vesta and how they compare with the HST results obtained during the 1994 opposition.