The Disk-Outflow System around the Rare Young O-type Protostar W42-MME
Abstract
We present line and continuum observations (resolution ~0.″3-3.″5) made with the Atacama Large Millimeter/submillimeter Array (ALMA), Submillimeter Array, and Very Large Array of a young O-type protostar W42-MME (mass: 19 ± 4 M ⊙). The ALMA 1.35 mm continuum map (resolution ~1″) shows that W42-MME is embedded in one of the cores (i.e., MM1) located within a thermally supercritical filament-like feature (extent ~0.15 pc) containing three cores (mass ~1-4.4 M ⊙). Several dense/hot gas tracers are detected toward MM1, suggesting the presence of a hot molecular core with a gas temperature of ~38-220 K. The ALMA 865 μm continuum map (resolution ~0.″3) reveals at least five continuum sources/peaks (A-E) within a dusty envelope (extent ~9000 au) toward MM1, where shocks are traced in the SiO (8-7) emission. Source A associated with W42-MME is seen almost at the center of the dusty envelope and is surrounded by other continuum peaks. The ALMA CO (3-2) and SiO (8-7) line observations show the bipolar outflow extended below 10,000 au, which is driven by source A. The ALMA data hint at the episodic ejections from W42-MME. A disk-like feature (extent ~2000 au, mass ~1 M ⊙) with velocity gradients is investigated in source A (dynamical mass ~9 M ⊙) using the ALMA H13CO+ emission, and it is perpendicular to the CO outflow. A small-scale feature (below 3000 au), probably heated by UV radiation from the O-type star, is also investigated toward source A. Overall, W42-MME appears to gain mass from its disk and the dusty envelope.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2022
- DOI:
- 10.3847/1538-4357/ac36dd
- arXiv:
- arXiv:2111.01373
- Bibcode:
- 2022ApJ...925...41D
- Keywords:
-
- 837;
- 694;
- 834;
- 52;
- 1569;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 28 pages, 14 figures, Accepted for publication in The Astrophysical Journal