Dr. Kamber Schwarz, NASA Sagan Postdoctoral Fellow, The University of Arizona
Molecular Tracers of Temperature, Mass and Carbon Abundance During Planet Formation
The final properties of planetary systems depend on the gaseous disk from which they form. However, basic properties such as the total disk mass remain difficult to constrain, as much of the protoplanetary disk is too cold for the main gas constituent, H2, to emit. Further, recent surveys reveal many disks have low CO-to-dust ratios, suggestive of substantial chemical evolution. Converting observations into physically meaningful properties often requires knowing the temperature of the emitting material. However, the temperature in a given protoplanetary disk varies by several orders of magnitude, such that simple temperature prescriptions are often insufficient. Thus, determining the basic disk properties of disk mass, temperature, and CO abundance requires the use of multiple tracers. In this talk I will discuss results from my recent study of the protoplanetary disk GM Aurigae as part of the ALMA large program “Molecules with ALMA at Planet-forming Scales.” Using new and archival ALMA observations, we construct a disk physical/chemical model which reasonably reproduces the spatially resolved CO isotopologue emission, millimeter dust continuum, and the unresolved HD detection from Herschel. Our analysis reveals the Gm Aurigae disk to be massive, cold, and missing the majority of its gas phase carbon.


Dr. Juliette Becker, 51 Pegasi b Postdoctoral Fellow, Caltech
Lifetimes of Multi-Planet Systems Around Evolving Stars


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