CO observations of NGC 1579 (S222) and S239.
Abstract
The 2.6-mm lines of (C-12)O and (C-13)O have been observed toward the small galactic diffuse nebulae NGC 1579 (S222) and S239. The H92-alpha recombination line has also been detected from NGC 1579. Toward NGC 1579, evidence was observed for self-absorption in the (C-12)O line. For both regions, high-velocity wings and line broadening are observable in the (C-12)O line; the features observed toward S239 suggest ordered free-fall collapse of a localized region of the cloud onto a newborn stellar cluster. Examination of the available data suggests that NGC 1579 is both a reflection nebula (illuminated by LKH-alpha 101) and an obscured H II region excited by a star of spectral type near B1, while S239 is a reflection nebula or a Herbig-Haro object. The present studies of these regions show that line widening in CO is at least as important an indicator of star-formation activity as enhanced line emission.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1976
- DOI:
- 10.1086/154399
- Bibcode:
- 1976ApJ...206..443K
- Keywords:
-
- Carbon Monoxide;
- Interstellar Matter;
- Molecular Spectra;
- Nebulae;
- Radio Spectra;
- Astronomical Models;
- Brightness Temperature;
- Cosmic Dust;
- H Alpha Line;
- H Ii Regions;
- Radial Velocity;
- Stellar Evolution;
- Astronomy