IRAM Seminar: Jenny Calahan

Determining the Mass and Gaseous-Chemical Reservoir of Outbursting YSOs using NOEMASeminar by Jenny Calahan (Harvard), 18 March 2024, 16h CET (15h UT)
Young stellar objects are thought to commonly undergo sudden accretion events that result in a sudden rise in bolometric luminosity. This outburst likely corresponds with the onset of planet formation, and could impact the formation of planets. The reason behind this dramatic enhancement of accretion is an active area of research, and the mass of the system is a critical clue. Using Northern Extended Millimeter Array, we survey five FU Ori-like objects with the primary goal of determining the system’s mass using an optically thin line of CO. We estimate the mass of a central region for each object using both continuum and C17O emission. The C17O emission likely includes both disk and inner envelope material, with masses ranging from 0.33-3.1 M_sun suggesting that these inner regions are gravitationally unstable. In addition to the mass determinations, we identify bright lines captured over NOEMA’s wide bandwidth. In all sources we see multiple lines of SO and H2CO in addition to the common CO isotopologues. One source, V1057 Cyg shows 48 individual transitions among 12 different molecular species. The disks and central regions around outbursting young stellar objects appear to be massive objects, often containing envelope emission putting these sources on the edge of Class I/II sources.