Projects of the Interstellaire team
Despite the harsh conditions reigning in the interstellar medium (ISM), many molecules are found in the regions where UV photons cannot penetrate. These regions, called molecular clouds, present the physical conditions favourable to the existence of a wide variety of molecules. Today, more than 180 molecules have been detected in such environments, from the simplest diatomic ones to more complex ones containing up to 12 atoms, as well as complex organic molecules such as formamide, a key species in the prebiotic synthesis of both metabolic and genetic species. Understanding the physics and chemistry of molecular clouds is a field of research at the intersection of several disciplines : astrophysics, astrochemistry, cosmochemistry and exobiology. Identifying and understanding the processes that govern the physico-chemical evolution of molecular clouds and star forming regions they contain, is the cornerstone of ASTROMOL team.
The major astrochemistry questions tackled in the ASTROMOL team are :
- What is the ultimate chemical complexity that can be reached in the ISM and, more specifically, during the process of formation of stars like our Sun and planetary systems like our Solar System ?
- How and when interstellar molecules are synthesised in that process ? More specifically, which molecules are formed in the gas phase and what on the surface of the interstellar grains ? What are the basic processes at work ?
- Is the material synthesised in the early stages of star formation inherited by the planets and planetary bodies (comets, asteroids…) ultimately formed ?
How stars are born in molecular clouds from the collapse of interstellar matter is a fascinating and yet unresolved question. Our group is interested in the physics, dynamics, and chemistry during the various evolutionary stages of the process. In particular we study the cold prestellar phase, protostellar envelopes and hot corinos, outflow phenomena and the gas in circumstellar disks, with state-of-the-art ground-based and space telescopes, from infrared to millimetre wavelengths.
Our research is concerned with the theoretical study of molecular collisions relevant mainly to astronomical environments, with particular emphasis on low temperature processes (T < 300K). We calculate both reactive and non-reactive (inelastic) cross sections using statistical, quasi-classical, semi-classical and quantum scattering methods. Our current interests include rovibrational excitation of atoms and molecules (by neutrals and electrons), pressure broadening of molecular transitions (e.g. CO, H2O), fast reactions involving small radicals and ions and proton/deuteron scrambling reactions. We are also interested in solid phase processes relevant to interstellar/cometary ice chemistry.
The largest part of our Universe is extremely cold : the Cosmic Microwave Background is at 2.725 K, the distant galaxies appear cold because of the redshift effect, and the temperature of most of the interstellar gas and dust in the Milky Way is between 10 and 20 K. The group studies the CMB primary and secondary anisotropies and its foregrounds (the interstellar matter). For that purpose, the continuum emission and polarization are observed in the (sub)millimetre domain via the ESA Planck satellite and a KID millimetre array (NIKA) at the IRAM 30m telescope.