The Role of Disk Volatile Chemistry and Dynamics in Shaping the Compositions of Nascent Planets
Abstract
The elemental composition of planets define their chemistry, and could potentially be used as beacons for their formation location if the elemental gas and grain ratios of planet birth environments, i.e. protoplanetary disks, are well understood. In disks, the ratios of volatile elements (e.g., C/O) is regulated by the presence of snowlines of major volatiles at different distances from the central star. We explore the effects of dynamical processes, such as radial drift of solids and viscous gas accretion onto the central star, molecular compositions, and the ice morphology of dust grains in disks on the snowline locations of the main C, O and N carriers in a protoplanetary disk, and their consequences for the C/O/N ratio in gas and dust throughout the disk. We find that radial drift and accretion alone can reduce the snow line radii by 40-60% of the main C and O carriers, i.e. H2O, CO2 and CO, compared to static disks, substantially changing the disk regions where C/O is enhanced over the stellar value. A similar effect is seen for the major nitrogen carriers. We note that N/O enhancements in disk gas can be even more extreme than C/O in the outer disk due to the low volatility of N2 compared to all major C and O carriers. I will discuss these results together with the effects of additional dynamical processes, and outline a path toward a coupled drift-desorption-chemistry model that will provide robust quantitative results for volatile snowline locations and C/N/O abundance ratios as the disk evolves in time.
- Publication:
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American Astronomical Society Meeting Abstracts #227
- Pub Date:
- January 2016
- Bibcode:
- 2016AAS...22732203P