Some meteorites contain xenolithic clasts that are made of material genetically unrelated to the host rock. Xenolithic clasts can be composed of materials not sampled by meteorites. They may potentially represent an underexploited source of primitive, volatile-rich material. During the four-year CLASTS project, we will combine petrographic, mineralogical, spectral, isotopic and chronological approaches in order to 1. Identify and determine primary characteristics and parent body history of xenolithic clasts in a series of meteorites from the CC and NC reservoirs, 2. Characterize primordial planetesimals no longer present in the asteroid belt through the study of clasts composed of materials not sampled in the meteorite collection; 3. Constrain the incorporation mechanism (primordial vs. subsequent accretion) and timing of the clasts in their host rock. CLASTS will leverage the complementary range of analytical and scientific expertise present in IPAG, CEREGE, CRPG and OCA.

ABSTRACT. In regions of active star formation, the protoplanetary discs around young stars act as planetary factories. Recent observing campaigns have shown that the majority of protostars belong to multiple stellar systems: the younger the stars, the higher the degree of multiplicity. Young discs are then strongly affected by stellar multiplicity, unavoidably modifying the way in which planets form. The detailed evolution of multiple systems with discs and planets however remains to be explored. Since most current models have been designed for single stars, there is an urgent need to extend these models to multiple stars. This will pave the way for a better understanding of the process of planet formation within our galaxy. The Stellar-MADE project aims to provide a comprehensive view of disc dynamics and planet formation within multiple stellar systems. My team and I will thoroughly study multiples to: (1) Establish the formation channels of protoplanetary discs around young stellar objects; (2) Follow disc dynamics and grain growth in order to identify the regions of planetesimal formation; (3) Characterise planetary architectures and the resulting exoplanet population. To achieve our goals we will perform hydrodynamical and N-body simulations, developing and adapting state-of-the-art codes (Phantom, mcfost, Rebound). Our calculations will include a broad range of physical processes: disc thermodynamics, radiative transfer, gravitational perturbations, aerodynamic friction, dust growth, and Mean-Motion Resonances. This will allow us to identify and quantify stellar multiplicity effects across evolution. My previous work on binary stars constitutes proof-of-concept that it is possible to coherently connect protoplanetary disc evolution to planetary architectures. Unveiling the effects of stellar multiplicity on planet formation will be a major breakthrough. PROJECT OBJECTIVES. The aim of this project is to study the impact of stellar multiplicity on planet formation: from the onset of disc formation in gaseous clouds to the final stage where stars host stable planetary systems. Three scientific questions will drive the proposed investigation: i) What are the initial protoplanetary disc conditions around young stellar multiple objects? ii) Where do solid bodies and planetesimals grow within discs in multiple stellar systems? iii) What are the most stable planetary architectures in multiple stellar systems? SCIENTIFIC IMPACT. This project will unveil the effects of stellar multiplicity on planet formation, which will allow us to interpret the whole exoplanetary population under a new prism. Our expected results will become the stepping stone for future research on multiple stellar systems. As a matter of fact, stellar multiplicity is the norm – rather than the exception – in active star-forming regions. It is therefore key to understand the impact of stellar multiplicity on planet formation. The ground- breaking nature of this proposal will guarantee a high impact at the international level, placing the Stellar- MADE team at the forefront of the emerging field of research on disc and planet dynamics in multiples. Our results are expected to open new avenues for studying the disc chemical reservoir across stellar evolution, planetesimal formation, and its impact on exoplanet composition.

The discovery of extrasolar planets is a revolution in modern astrophysics which impacts not only our knowledge of planet formation and evolution, but also our understanding of the place of the Earth in the Universe. In this domain major advances have been made by using spectroscopic observations of transiting planets. Using this technique, we discovered an unexpected phenomenon : the evaporation of hot-Jupiters, and we made a detailed study of the atmosphere of the exoplanets HD209458b and HD189733b. Observations of transiting planets are now widely recognized as a powerful method to scrutinize the atmosphere of these exoplanets. The present “Exo-Atmos” programme is aimed at constraining both the extended upper atmosphere of evaporating planets, and the deeper atmosphere of a large variety of exoplanets, using transit spectroscopy observations. These objectives will be reached by two means: 1) We will observe with the best telescopes presently available: Very Large Telescope (VLT) and the Hubble Space Telescope (HST). 2) We will also enlarge the sample of planets for which atmosphere are detected and analysed. Indeed, we have obtained a large amount of time on the HST and the VLT telescopes to observe the atmospheres and evaporation of extrasolar planets. For instance, with 3 HST programs in 2012 we will observe a total of 10 planets (9 exoplanets + Venus as a benchmark). This will allow us to scrutinize the atmosphere of an unprecedented large sample of exoplanets, and will open the field of comparative exoplanetology. However, to obtain the best scientific return of these programs, a substantial financial support is required. Here we propose an ANR program to support this work. In addition to financial support for missions and equipment, we ask for 2 post-doctoral fellowships of 2 years, one for each of the two partners of the project. Finally, we ask for financial support for the acquisition of a powerful computer that will be dedicated to numerical simulations for the analysis and interpretation of HST spectroscopic observations, and modeling of the gas escape. These simulations will be designed to better constrain the structure, dynamics and composition of the atmospheres of planets observed by transit spectroscopy. In particular, a significant part of the CPU time will be dedicated to issues related to the evaporation of planets orbiting close to their star, an area in which our team has played a major role. Combined with the results of these simulations, the HST observations will allow to better constrain the escape rate and the evaporation mechanisms. At the end of this 3 year program "Exo-Atmos," we aim to better understand the atmosphere and evaporation of exoplanets.

Pre- and protostellar cores represent the earliest stage of the formation of a star. This phases are crucial for the future evolution of the star, as its final mass and the initial composition of the proto-planetary disk that may eventually form planet will be determined during these phases. In the past years, much progress has been done in our understanding of the chemical structure of these objects, thanks to the dramatic increase of the sensitivity of millimiter and sub-millimeter ground based telescopes. In fact, it is now possible to use chemistry as a tool to constrain both physical and chemical characteristics of these objects. However, most studies so far have used single dish observations with typical resolutions of a few tens of arc seconds, and the physical and chemical structures if cores on smaller scales remains poorly know. Here we propose to carry-out a study the physical and chemical properties of a large sample of Class 0 protostars, using both an observational and theorical/modelling approach. Our observations are part of an extensive survey of the line and continuum emission from young protostars with the Plateau de Bure interferometer at sub-arcsecond resolution. Follow-up observations with ALMA and NOEMA will be carried-out. We propose to develop a new chemo-dynamical model combining the results of state-of-the art MHD simulations of core collapse with a complete chemistry network and a radiative transfer model. The direct comparison between sub-arcsecond resolution observations and the predictions our chemo-dynamical model is expected to bring important constraints on the formation and evolution of pre- and protostellar cores, and in turn on star formation theories.

Giant planets (GP) are major players in the building-up of planetary systems; a good knowledge of the giant planet population is then necessary to get a full understanding of planetary system formation and evolution. Yet, we have only a very partial view of the extrasolar GP populations, because RV/transit technics are sensitive to planets close to the stars, and up to now, direct imaging techniques were sensitive to far away planets (> 10 AU tyP.). Moreover indirect and direct techniques do not consider the same targets (MS stars for the indirect and young stars for the direct techniques). For no star do we have today a complete exploration of its giant planet population today. A solar-system analogue is out of reach of present detection capabilities, for telluric planets, but also for giant planets, and a full exploration of the GP population around mature, solar-type MS stars will not be possible before one or two decades. We propose here to bridge the present gap for the first time. To do so, we will 1/ undertake the first complete exploration of giant planets, from tenths to hundreds of AUs around a well-chosen sample of young stars, 2/ derive quantitative statistical information on GPs properties, 3/ deduce constraints on GP formation and early (first hundreds Myrs) evolution mechanisms, and 4/ perform detailed various studies of individual systems. Our project is now possible thanks to two concomitant progresses: the arrival of high performance planet imagers, dedicated to the detection and characterization of planets around young stars on the one hand, and, on the other hand, the maturity of the analysis techniques of radial velocity data that allow now searching for planets around young (and active) stars. We have selected a sample of stars in nearby, young stellar associations that are suited for both radial velocity studies and direct imaging. Thanks to these unique results, we will constrain the processes of planetary system formation (prevalence of core accretion versus gravitational instability within a disk, constraints on initial conditions), the evolution processes (disk-planet migration versus planet-planet interaction), and their associated timescales. Detailed studies will also help understanding individual systems. Such studies are proven to be very precious to progress in the field so far. Our team has a strong experiment and records in high contrast imaging of exoplanets on the one hand (PI/PS of NACO and forthcoming SPHERE on the VLT; discovery and studies of several exoplanets in direct imaging), as well as in radial velocity techniques (development and successful use of tools that allow to measure precise radial velocities of rapidly rotating stars, discoveries of radial velocity planets, feasibility study of the detection of giant planets around young -and active- stars; quantitative studies of the impact of stellar/solar activity on the detectability of exoplanets).