Large total masses and small amounts of CO gas in protoplanetary disks
Abstract
The total mass in protoplanetary disks and the C-to-O ratio of solids and gas are critical initial conditions for understanding the speed of planet formation and planetary composition after formation. Several recent studies show that the standard assumptions for both of these quantities are likely incorrect. I will report on our new set of models that reconcile theory with observations of protoplanetary disks and create a new set of initial conditions for planet formation models. This modeling makes use of recent resolved multiwavelength observations of disks in the millimeter to constrain the aerodynamic properties of dust grains, allowing us to infer total disk mass without an assumed dust opacity or tracer-to-H2 ratio. The 7 disks modeled using this method thus far are close to the limit of gravitational stability at certain radii and raise the possibility that all disks are more massive than has been previously appreciated. This qualitative change to the initial conditions of planet formation has sweeping implications. I will present new, unpublished work that combines the microphysics of cloud formation in planetary atmospheres and our new models of protoplanetary disks to show that the observed depletion of CO in TW Hya is consistent with freeze-out processes and that the variable CO depletion observed in disks can be explained by the processes of freeze-out and particle drift. This work both solves an outstanding problem in observations of protoplanetary disks and robustly constrains the C-to-O ratio in gas and solids available for planet formation.
- Publication:
-
AAS/Division for Extreme Solar Systems Abstracts
- Pub Date:
- August 2019
- Bibcode:
- 2019ESS.....450102P