Observing Disk Accretion in Action - Joan Najita (NOIRLab)

Origins Seminar presented on November 16, 2020.

Title: Observing Disk Accretion in Action

Speaker: Joan Najita, NOIRLab

Abstract:
Physical processes that redistribute or remove angular momentum from protoplanetary disks can drive mass accretion onto the star and affect the outcome of planet formation. Despite ubiquitous evidence that disk are accreting, the process(es) responsible remain unclear. I will describe new results from that appear to show disk accretion in action: rapid inflow of molecular gas at the surface of a protoplanetary disk. High-resolution mid-infrared spectroscopy of the Class I source GV Tau N reveals a rich redshifted absorption spectrum of individual lines of C2H2, HCN, NH3 and H2O. The properties of the absorption indicate that the flow carries a significant accretion rate, comparable to stellar accretion rates of active T Tauri stars. The results may provide evidence for supersonic “surface accretion flows,” which have been found in MHD simulations of magnetized disks.