Astronomy Colloquium

  In this talk I will focus on two aspects of planet formation that have potential observational signatures that should be present in molecular emission associated with gas-rich disks.  First, in the early stages of disk evolution, settling of ice-coated dust grains to the midplane should lead to the sequestration of the disk's icy solidsinto the planet feeding zone.  Thus, beyond their snow lines volatiles (CO, H2O, N2) condense and become incorporated into any forming planetesimals.  We suggest that over time this process must deplete  the upper atmosphere of these important volatile reservoirs.  I will present evidence that this process might be active in a nearby disk. This work has broad implications for estimates of  disk gas mass and gas dissipation timescales from species such as CO will consequently be intertwined with the timescales of planet formation. In this second part of my talk, I will focus on exploring the possibility that forming gas giants might be detected via disk chemistry using ALMA.  Thus I will present a 3D physical/chemical model that includes two point sources: star and accreting protoplanet. With generic assumptions based on planet formation theory and observations, we find that the localized heating of an accreting protoplanet can alter the chemistry in its near vicinity by, for example, releasing volatiles that otherwise would be frozen on grain surfaces. I will show that this effect is present and predicted to be detectable, perhaps opening up the submm/mm-wave to planet searches.