James Webb Space Telescope Feed Post

Arxiv: CORINOS II. JWST-MIRI detection of warm molecular gas from an embedded, disk-bearing protostar Published: 7/22/2024 3:07:17 AM Updated: 7/22/2024 3:07:17 AM

Paper abstract: We present James Webb Space Telescope (JWST) Mid-InfraRed Instrument (MIRI)observations of warm CO and H_2O gas in emission toward the low-massprotostar IRAS 15398-3359, observed as part of the CORINOS program. The CO isdetected via the rovibrational fundamental band and hot band near 5 \mum,whereas the H_2O is detected in the rovibrational bending mode at 6-8 \mum.Rotational analysis indicates that the CO originates in a hot reservoir of1551\pm135 K, while the water is much cooler at 212\pm 2 K. Neither the COnor the H_2O line images are significantly spatially extended, constrainingthe emission to within ~40 au of the protostar. The compactness and hightemperature of the CO are consistent with an origin in the embeddedprotostellar disk, or a compact disk wind. In contrast, the water must arisefrom a cooler region and requires a larger emitting area (compared to CO) toproduce the observed fluxes. The water may arise from a more extended part ofthe disk, or from the inner portion of the outflow cavity. Thus, the origin ofthe molecular emission observed with JWST remains ambiguous. Better constraintson the overall extinction, comparison with realistic disk models, and futurekinematically-resolved observations may all help to pinpoint the true emittingreservoirs.