Big Apple Colloquium by Karin Öberg, Harvard University
Planets form in disks around young stars. The resulting planet compositions are intimately linked to the disk chemical structures; the distribution of molecules across disks regulate the elemental compositions of planets, including C/N/O/S ratios and metallicity (O/H and C/H), as well as access to water and prebiotically relevant organics. These molecules are in part inherited from earlier stages of star formation, and in part formed in situ in disks. In this talk I will present our developing view of the molecular cloud and protostellar chemistry that sets the initial chemical conditions in planet forming disks. I will then turn to recent gains made in our understanding of disk chemistry through the Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program. With MAPS we have been exploring disk chemical structures down to 10 au scales in a small sample of disks in which dust substructures are detected and planet formation appears to be ongoing. Some highlights include discoveries of links between dust and chemical sub-structures, large reservoirs of nitriles and other prebiotically interesting organics in the inner disk regions, elevated C/O ratios across most disks, and low gas depletion levels in most dust gaps. I will discuss how these results are reshaping our view of the chemistry of planet formation, but also review some open questions that remain and the observations, models and laboratory experiments that will be needed to address them.
Possibly followed by a social event, depending on Covid situation.