An Evolved Protostellar System Still Growing Fast
Released: 18th. February, 2022, Academia Sinica, Institute of Astronomy & Astrophysics (ASIAA), Taiwan
Outflows and jets in protostars are the most fascinating characteristics of stellar accretion. Jets carry away excess angular momentum from the inner-disk around protostar and allow material to fall into the central core, hence the central core grows up to become a true star like our Sun. The Atacama Large Millimeter/submillimeter Array (ALMA) observations by a team of astronomers led by Postdoc Fellow Somnath Dutta and Research Fellow Chin-Fei Lee in ASIAA have detected the oldest SiO jet from a protostar to date, at an unprecedentedly evolved stage than found by most observations. They observed G205.46-14.56S3 (HOPS 315) dense core, an isolated system located in Orion molecular cloud, as a part of "ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP)". The core is evolved to a Class I system and exhibits low-density wide-angle outflow. The high-velocity jet is not only detected in CO but also in SiO molecular transition. The source is confirmed as Class I by comparing sub-mm flux and luminosity with other literature samples.
ALMA SiO map of G205.46-14.56S3 jet, shown in color, with CO contours overplotted for blueshifted (blue) and redshifted (red) lobes. Credit: ALMA (ESO/NAOJ/NRAO)/Dutta et al.
Flux vs bolometric luminosity for Class 0 (red circle) and Class I (black square), for the ALMASOP sources from Dutta et al. (2020). The star mark indicates G205.46-14.56S3 source. The solid black line is the best fit for the Class I and brown line is the best fit for Class 0 sources. Credit: Dutta et al.
This research was presented in the paper: ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of a Dense SiO Jet in the Evolved Protostellar Phase, in The Astrophysical Journal 925, 11