JCMT Observations of the Ionizing Stars in the HII Region W40
Abstract
Continuum observations of the main ionizing stars OS1a, OS2a, and OS3a in the H II region/molecular cloud W40 were made with the James Clerk Maxwell Telescope in Hawaii, in August 1991, January 1992, and June 1993. OS1a was detected at a level of 56 +/- 18 mJy at 1.1 mm wavelength. OS2a was detected with a mean of 256 +/- mJy at 1.1 mm, and at 654 +/- 160 mJy at 0.8 mm. OS3a was not detected at 1.1 mm. These mm-submm observations imply the existence of substantial circumstellar material around the main ionizing star OS2a (approx. 0.1 solar mass), and a smaller amount around OS1a (approx. 0.02 solar mass). Only an upper limit is inferred for OS3a.
- Publication:
-
The Astronomical Journal
- Pub Date:
- September 1994
- DOI:
- 10.1086/117129
- Bibcode:
- 1994AJ....108..998V
- Keywords:
-
- Cosmic Dust;
- Emission Spectra;
- H Ii Regions;
- Ionization;
- Main Sequence Stars;
- Mass;
- Massive Stars;
- Stellar Envelopes;
- Stellar Physics;
- Astronomical Observatories;
- Bolometers;
- Graphs (Charts);
- Molecular Clouds;
- Spectrum Analysis;
- Tables (Data);
- Astronomy;
- HII REGIONS;
- ISM: INDIVIDUAL: MOLECULAR CLOUD W40