better exoplanet searches through chemistry

Today I had the great privilege of spending the day with the group of Karin Öberg (CfA) at Harvard and also the NG Next team. Öberg's group is doing so many great things, related to astronomical observations of proto-planetary disks and also real lab experiments on ices and solid-state chemistry relevant to interstellar and accretion-disk physical conditions. Here are some highlights:

Ellen Price (CfA) showed a consistent chemical model in which they evolve the molecular contents of gas as it orbits in the evolving accretion disk. This is based on a NLTE chemical model built by Ilse Cleeves (CfA). She can see big changes as gas crosses the snow line (or various snow lines for different species). Edith Fayolle (CfA) showed absolutely incredible ALMA observations they have (with Cleeves and also Ryan Loomis, CfA) of proto-planetary disks around young stars. In these observations, there is so much, I could fill a whole separate set of blog posts: They see various kinds of organics that weren't expected to be formed in abiotic conditions. They also can image the disk in two spatial dimensions and the radial velocity dimension in thousands of chemical species. This is unprecedented detail on a disk, and also unprecedented information about molecules in these conditions. We discussed ways we could simultaneously model all of this and make very sensitive measurements of what is going on at various laces in the disk. As part of this discussion, Öberg and I discussed the problem that there isn't a good out-of-the-box imaging pipeline for ALMA, in part because different users with different targets have very different priors and goals.

But then we switched to lab stuff! Mahesh Rajappan (CfA) described the Öberg-lab experimental setups, in which they can deposit ices, including multilayer things, and then radiate them or heat them, to measure solid-state chemistry processes directly. Jennifer Bergner (CfA) is doing lab experiments to find and measure configurational rate constants for chemical processes in ices. These rates relate to the processes by which molecules find one another and reorient to permit solid-state reactions to take place. She was working in particular on O+CH4 to CH3OH. One theme of the day's conversations is that the organic chemistry of proto-planetary disks is seriously complex and contains everything that is needed for life (we think).

At the end of the day we discussed research synergies. I think the biggest is in building consistent models of the thousands of molecules, in the dynamical disk. One incredible idea is that a forming gas-giant planet should be hot (gravitational or accretion energy); this could affect the local chemistry in the disk: We could see the thermal signature of a forming planet in molecular species! That's a great goal for the near future. Öberg's group (and especially Cleeves and Loomis) have the data in hand, or coming when ALMA gets to their targets.

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