We have observed the Class I protostellar source Elias 29 with Atacama Large Millimeter/submillimeter Array (ALMA). We have detected CS, SO, 34SO, SO2, and SiO line emissions in a compact component concentrated near the protostar and a ridge component separated from the protostar by 4" (∼ 500 au). The former component is found to be abundant in SO and SO2 but deficient in CS. The abundance ratio SO/CS is as high as 3+13−2 ×102 at the protostar, which is even higher than that in the outflow-shocked region of L1157 B1. However, organic molecules (HCOOCH3, CH3OCH3, CCH, and c-C3H2) are deficient in Elias 29. We attribute the deficiency in organic molecules and richness in SO and SO2 to the evolved nature of the source or the relatively high dust temperature (≳ 20 K) in the parent cloud of Elias 29. The SO and SO2 emissions trace rotation around the protostar. Assuming a highly inclined configuration (i ≥ 65◦; 0◦ for a face-on configuration) and Keplerian motion for simplicity, the protostellar mass is estimated to be (0.8 - 1.0) M☉. The 34SO and SO2 emissions are asymmetric in their spectra; the blue-shifted components are weaker than the red-shifted ones. Although this may be attributed to the asymmetric molecular distribution, other possibilities are also discussed.
|Publication status||Published - 2019 Jun 24|
- ISM: individual objects (Elias 29)
- ISM: molecules
- Stars: formation
- Stars: pre-main
ASJC Scopus subject areas