I began the project by analyzing near-infrared spectra for a sample of 26 young, low-mass stars surrounded by protoplanetary disks. I identified and measured line fluxes for emission lines produced by elements of interest to ice and rock-formation during planet formation, as discussed above: carbon, hydrogen, oxygen, nitrogen, magnesium, sodium, silicon, aluminum, calcium, and iron. I used the publicly available photoionization and chemistry modeling code, Cloudy, and plasma code CHIANTI to make models of the 5 disks with the best quality spectra to measure the carbon abundance in their inner disks. This resulted in one paper, McClure (2019). Next we analyzed the near-infrared spectrum of the most nearby disk, TW Hya, for which multiple epochs of spectroscopy are archivally available. By subtracting the spectrum from a low-accretion epoch from that of a higher accretion epoch, we were able to separate out the emission contribution from the gas being accreted from the inner most disk. By constructing a Cloudy model to include all of the emission lines we discovered in the residual spectrum, we were able to obtain abundances for all of the elements discussed above. The results showed that all of the elements were depleted in abundance relative to hydrogen, suggesting that extrasolar gas giant planets formed in this region would have depleted atmospheres (McClure & Dominik, 2020, under review). The depletion of these elements suggests that they have been left behind in solids in the disk. We also determined at what time these solids began to be retained in this disk, i.e. at what time planetesimal formation started (McClure, Dominik, & Kama, in prep.), finding that it must happen at <100,000 years. We disseminated these results at 1) a number of conferences for astronomers, as well as separate conferences for the fields of planetary science and chemistry, 2) events for undergraduate and masters students, 3) a public outreach evening at the university.
