The Chemistry of Planet Formation

SFB Colloquium
Dr. Catherine Walsh
University of Leeds, UK

Protoplanetary disks around young stars are the factories of planetary systems. These structures contain all the material - dust, gas, and ice - that will build planets and other bodies such as comets. Hence, understanding the physics and chemistry of disks provides much needed insight into the conditions under which planets form, and determining their molecular content reveals the raw ingredients of planetary atmospheres. In this colloquium I will present early results from the first ALMA Large Program dedicated to the observation of molecular line emission from protoplanetary disks around nearby young stars at high angular resolution (0.1'' - 0.3''), titled Molecules with ALMA on Planet-Forming Scales or MAPS. I will present images that reveal intriguing sub-structure in emergent line emission from key organic molecules such as CO, C2H, HCN, and CH3CN.  I will discuss the link between known dust substructure and the observed line emission, and will present results from quantitative analyses of source properties such as radial mass distribution, chemical structure, ionisation structure, and elemental composition of the gas.  I will also discuss how observations in the gas-phase of large organic molecules provide insight into the composition of the icy-comet building reservoir around other stars. Finally I will discuss how early results from MAPS have provided the most detailed studies to date of the chemistry of planet formation.

Astrochemistry and Compositions of Planetary Systems

Main Colloquium
Prof. Karin Öberg
Harvard University, Cambridge, USA

The past decades have revealed that planets are incredibly common, and incredibly diverse. The origins of planets and their compositions are intimately linked to the chemical environments within which planets assemble, i.e. to the chemistry of planet-forming disks. The arrival of ALMA has provided observational access to disk chemistry, revealing disk snowlines, abundant organic molecules, and curious chemical gradients and sub-structures across the planet and comet forming zones. The most recent development is the execution of the ALMA Large Program MAPS (Molecules with ALMA on Planet-forming Scales), which has enabled us to zoom in on disk chemical structures at scales of 10-30 au. In parallel to these observational developments, astrochemistry models and laboratory experiments are providing new clues on what chemistry is likely to occur in different disk environments. I will present highlights from the MAPS program, as well as some recent laboratory astrochemistry discoveries. I will discuss how these new observational and laboratory data are affecting our understanding of the chemistry of planet formation, the chemical habitability of mature planetary systems, and the history of our own Solar System.