LPL Colloquium: Dr. Rachel Smith

Temporal Variability in Young Stellar Objects and Implications for the Early Solar System

Dr. Rachel Smith
Head, Astronomy & Astrophysics Research Laboratory
North Carolina Museum of Natural Sciences

High-resolution near-infrared observations of young stellar objects (YSOs) provide a unique window into protoplanetary chemistry and a range of insights into key molecular processes. While spectral observations of YSOs are considered snapshots in a one- to a few-million-year(s) timescale, these dynamic objects have also been shown to vary in infrared fluxes and amplitudes within only a few months to years, possibly due to variations in disk geometry, dynamics, and/or magnetic field influences. In this talk I will present results from our new study of CO column density and gas temperature short-term variability observed toward solar-type and massive YSOs. Using high-resolution infrared rovibrational spectra, CO isotopologue column densities and gas temperatures were found to vary significantly between observing epochs, with variation in isotopologue ratios further suggesting that phenomena with preferential isotopologue effects, such as CO self-shielding, could be influencing reservoirs over very short timescales. We thus far conclude that both short- and long-term variability in key molecular reservoirs should be included in protoplanetary disk models, and consideration be given to potential complications in interpretations of YSO observations in the context of the early solar nebula. This ongoing study includes new and upcoming observations at NASA’s Infrared Telescope Facility.

Host: Dr. Pierre Haenecour


November 19, 2019 3:45pm