The emergence of Life relied on the presence of key molecules like water and prebiotic molecules. The primitive objects of our Solar System (comets, asteroids), which formed in the disk of dust and gas surrounding the young Sun, are thought to have delivered them to Earth during heavy bombardments. Observations show that the deeply embedded Class 0 protostars also harbour a very rich chemistry in their inner regions. What occurs to the chemical composition between this early stage of the star formation process and the formation of planets, comets, and asteroids is unknown. Do the molecules detected in these young protostars survive or are they destroyed and reformed at a later stage before being incorporated into planets, comets, and asteroids? This ERC project aims to reconstruct the physico-chemical evolution from the deeply embedded protostellar stage to the planet forming disk stage, through multi-source analyses of high angular resolution observations combined with chemical modeling studies. I will investigate the evolution of complex organic chemistry and isotopic fractionation during the star formation process using interferometric observations (ALMA, NOEMA) of solar-type protostars. In addition, I will carry out numerical simulations with a state-of-the-art gas-grain chemistry code in order to interpret the observations as well as to characterize the impact of the physical conditions and their evolution (environment, grain growth and dust settling, episodic accretion) on the chemistry. This ERC project will lead to a new understanding of the evolution of the chemical composition from the earliest protostellar stage to the formation of the disk that will give birth to the planets, comets, and asteroids, while identifying the processes affecting the final composition of the disk. The observational work will require the development of innovative tools of interest for the astrochemical community that I will release publicly.

COLD-WORLDS aims to use gravitational microlensing to explore a unique niche, cold planets down to Earth mass orbiting around any kind of star, at any distance towards the Galactic center, rogue planets and moons orbiting exoplanets (exomoons). These are in very different environments from most known exoplanets, allowing key tests of planet formation theory. Indeed, the maximum sensitivity is for planets at the snow line, close their formation location. To date, 55 microlensing planets have been published and these results challenge theories of planet formation. The core accretion population synthesis predictions by Ida’s and Bern’s groups are quite similar and both under-predict the number of observed cold planets at a mass ratio of q =2E-4) by a factor of ~25. It might be due to the run-away gas accretion phase of planet formation, which is a basic feature of the core accretion theory. Alternatively, it could be that there is some host star mass dependence of this run-away gas accretion gap that smooths out this feature when plotted as a function of mass ratio. So, it is important to accurately determine the individual masses for the planets and host stars. Microlensing provides precise mass-ratio and projected separations in units of the Einstein ring radius. In order to obtain the physical parameters (mass, distance, orbital separation) of the system, it is necessary to combine the result of light curve modeling with lens mass-distance relations and/or perform a Bayesian analysis with a galactic model. Often, physical parameters are determined to 30-50 %, or even worse. However, we have shown that a tight constraint can be obtained on the lens mass-distance, thanks to detection or upper limits on its luminosity using high angular resolution observations with 8m class telescopes or HST. The pioneering work by our team shows that we can derive physical parameters on known systems to 10 % or better with Keck adaptive optics for instance. In the uncertainty budget, we would then be dominated by extinction correction, distance to the source, calibrating luminosity function of main sequence stars and our understanding of the galactic structure. COLD-WORLDS will use infrared wide field imagers (public surveys from VISTA, UKIRT, and dedicated observations) and operate adaptive optics on 10m class telescopes. We obtained data already on 30 systems (Keck, VLT, SUBARU, HST) and we have 10 nights approved as Key Strategic Mission Support to WFIRST with Keck for the years 2018-2019. By 2019, we will have observations of the host stars of ~100+ systems with cold planets. We will use Gaia DR2 to measure the source distances, revisit the galactic disk, bar, bulge. Combining Gaia with the multiband observations, we will revisit our model of extinction. It will also give the kinematics on the line of sights to the Bulge and will allow to revise our Bayesian modeling of microlensing plane. We will then perform demographics of the Disk and Bulge cold planet populations and address the following science objectives. 1/ What is the mass distribution of cold planets down to ~1 Earth mass at the snow line, where most planets are formed? 2/ What is the spatial distribution and abundance of cold planets towards the centre of our Galaxy? 3/ How to routinely achieve better than 10% accuracy in microlensing planet mass determinations with the next generation of satellites (Euclid and WFIRST)? 4/ Producing a near-infrared (JHK) photometric archive from ESO dedicated surveys of the Galactic bulge, a lasting resource for broad areas of stellar and galactic astronomy. Our highly dedicated team covers all the range of needed expertise. It is also using public data and has all the needed allocated telescope time. It is a risk free, high impact project, giving roots to the Euclid and WFIRST microlensing surveys, while providing important results and useful legacy products.

The formation of stars is intimately linked to the structure and evolution of molecular clouds in the interstellar medium (ISM). We propose to explore this link with a new approach by combining far-infrared maps of dust (Herschel) and cooling lines (C+ with SOFIA) with molecular line maps. Dedicated analysis tools will be used and developed to analyse the maps and compare them to simulations in order to identify for the underlying physical processes. This joint project relies on the complementary expertise of the members of the Cologne KOSMA group (structure identification methods and SOFIA), the Bordeaux LAB star formation group (Herschel and spectro-imaging maps) , and the Bordeaux GeoStat team of INRIA institute of applied mathematics (experts in nonlinear methods for the analysis of complex systems). To understand the genesis of stars, it is necessary to disentangle the relative importance of gravity, turbulence, magnetic fields, and radiation from diffuse gas, to molecular clouds and collapsing cores. Using novative new analysing tools developed by the GeoStat team, we will analyse the Herschel images as well as new spectro-imaging surveys from ground-based telescopes, and THz spectroscopy using SOFIA. The comparison with similar analysis on simulated clouds will allow us to derive the underlying physical process which explains cloud evolution and the formation of dense structures. We select template clouds that cover a representative parameter space of mass, temperature, and star-formation activity to test the different evolutionary stages and the diversity in star-forming clouds. Close collaboration with the Cologne group is required to profit from their long-lasting expertise of quantifying cloud structure (e.g. Delta-variance) and statistical measures (e.g. N-PDFs) for these innovative methods and analysis tools that will be developed by the Bordeaux partner (LAB) in an interdisciplinary effort together with GeoStat. We will also explore the coupling of turbulence with heating- and cooling processes that leads to structural changes and that may help us to improve our understanding of the role of feedbacks to regulate the star formation efficiency. More precisely we aim at identifying the spatial scales of the transition phase from atomic to molecular hydrogen, at determining the location of the dissipation of turbulence and get insight into other structure generating processes. The project does not aim at a full understanding of star formation within 3 years, but it constitutes an important step forward as it will make systematic use of a wealth of existing, yet not fully exploited archival data, carefully chosen new observations, and sophisticated tools to analyse and interpret the data. As such, it will shed new light on how molecular clouds and stars form and may well be the starting point for many studies to follow.

The objective of this interdisciplinary project is to quantitatively interpret the unexpected ALMA detection of ro-vibrationally excited water molecules in evolved stars from a theoretical, experimental and astrophysical point of view. To this end, the collisions of ro-vibrationally excited water molecules with H2, H, He and the electrons will be studied by taking for the first time into account, the coupling between the bending and rotation modes of water. In order to validate the calculations experimentally, the Bordeaux crossed-beam machine will be adapted to generate a supersonic jet of vibrationally excited water molecules. The third pillar of the project dedicated to the modeling of the ALMA data will integrate the new collision rates into an advanced radiative transfer code. The new experimental and theoretical results produced in the course of the project to model our star observations will also be applicable to the general interstellar medium.

How giant planets form is one of the major open issues in planetary science. Given that gas giants gravitationally dominate their planetary systems, this limits our understanding of the origin of planetary system architectures and the conditions needed for the formation of habitable terrestrial planets. The standard model of giant planet accretion (Pollack et al 1996) consists of two phases: the accretion of a solid rocky/icy core of several Earth masses and the formation of a massive atmosphere around such a core by the capture of gas from the circumstellar disk. However, each of these phases presents significant unsolved problems. First, the accretion of cores from a population of planetesimals seems to stall long before a mass of several Earth masses is reached. Second, simulations predict that the capture of gas by a massive core, once it enters a runaway phase, does not stop until several Jupiter masses of gas are accreted (unless some fine-tuning of the removal of the circumstellar gaseous disks is invoked), in clear conflict with the masses of Jupiter and Saturn and the population of giant extra-solar planets (in which Jovian and sub-Jovian planets are very abundant). With MOJO, we propose to carefully study these phases by combining comprehensive hydrodynamical simulations and N-body simulations of interacting planetary embryos embedded in circumstellar disks. We will test two promising new mechanisms for core accretion: (i) rapid formation of planetary embryos via the accretion of pebbles by the largest planetesimals and (ii) mutual accretion of the embryos due to convergent migration. The latter requires a realistic model of non-isothermal protoplanetary disks in which planetary embryos migrate via tidal interactions with the gas towards an equilibrium orbital radius. This equilibrium radius could be a sweet spot for the mutual accretion of embryos, leading to the formation of a few massive cores. Once embryos are massive enough to become giant planets, accretion of their envelope will be studied with a nested mesh code that can resolve the accretion flow and the circumplanetary disk. Recent results show that this disk should be much less ionized and viscous than the surface layers of the circumstellar disk. A low-viscosity circumplanetary disk may act as a bottleneck for gas accretion onto the planet, preventing the fast runaway phase. This process has the potential of increasing the gas accretion timescale, making it comparable with the disk lifetime. The diversity of giant planet masses may stem naturally from the similarities of these two timescales. Experience has taught us that the Solar System, with its numerous and precise observational constraints, is a key benchmark for formation models. Requiring exoplanet-oriented models to also match the Solar System has led to the identification of essential physical mechanisms that would have otherwise been missed. MOJO will thus focus first on giant planet formation in our Solar System. The study will then be applied to exoplanetary systems, for which constraints on both the giant planet and terrestrial planet populations are becoming more and more detailed thanks to numerous ground-based and space-based surveys. We will also study the consequences of the migration of the planetary embryos on the formation and survival of habitable terrestrial planets. Last but not least, images of protoplanetary disks with very high resolution (less than 10AU) are becoming possible with instruments such as ALMA and SPHERE. Our disk-planet models can be used to interpret these observations. With MOJO, we have assembled a team with a range of expertise necessary to develop a model that explains both the giant planets of our Solar System and the diversity of planetary systems.