SF-04-0051

JWST Observations of Young Protostars (JOYS): Program Overview and First Results

Logan Francis, Lukasz Tychoniec, Martijn van Gelder, Will Rocha, Ewine van Dishoeck, Mike Ressler, Henrik Beuther, Caroline Geiser, JOYS Team

On behalf of the JWST Observations of Young Protostars (JOYS) Team, I will present an overview and first results of MIRI MRS GTO programs 1290 and 1236. Observations from these programs will answer key questions about protostars by probing the composition of ices in the envelope and links to the gas phase, the properties of the atomic and molecular outflows, the rate of (episodic) accretion, and the conditions in the hot inner disk. The focus will primarily be on the young high mass source IRAS 23385+6035 and recent observations of low mass sources in Perseus and Taurus. The remarkable improvements in sensitivity and spectral resolution of MIRI over previous space facilities allow us to detect a plethora of ice absorption, PAH features, and emission lines. Absorption from various ices, including H2O, CO2, NH3, NH4+, and CH4, is clearly identified. Molecular emission from CO2 and several other molecules (CO, CH4, C2H2, HCN) is clearly detected, tracing the high temperature shocks (CO, OH) and the warm disk surface (CO2). LTE modeling of the emission allows tight constraints on the physical conditions of the disk and shocks to be placed. Notably, we also detect HD at the farthest known distance for an embedded protostar. IRAS 23385+6035 is resolved into a binary, for which we identify a dichotomy in the presence of hot (~1500K) CO emission and H2O absorption features, possibly related to a difference in disk inclination. A complex system of high velocity (>100 km/s) jets is well-traced by H2 and forbidden emission lines (e.g. [Fe II]). These exciting first results will be placed in the evolutionary and environmental context of our larger observing program using preliminary observations of other low mass star forming regions