Silicon monoxide in the 4 micron infrared spectrum of long-period variables.
Abstract
The first-overtone sequence of vibration-rotation transitions of the free radical silicon monoxide are shown to have extreme phase-dependent variations in the spectra of two M-type long-period variables, Omicron Ceti and R Leonis, and the mild S-type long-period variable, Chi Cygni. At maximum light, the SiO band heads are not detectable. Near minimum light, the band heads of (Si-25)O are detected in the 4-micron spectra of all three stars. The band heads of the terrestrially less abundant isotopic species, (Si-29)O and (Si-30)O, are detected in Chi Cygni. Possible explanations of the phase-dependent behavior are discussed, and the role of the stellar chromosphere is considered.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1976
- DOI:
- 10.1086/182324
- Bibcode:
- 1976ApJ...210L.141H
- Keywords:
-
- Infrared Spectra;
- M Stars;
- Silicon Oxides;
- Spectrum Analysis;
- Stellar Spectra;
- Variable Stars;
- Chromosphere;
- Electron Transitions;
- Free Radicals;
- Giant Stars;
- Molecular Spectra;
- Supergiant Stars;
- Astrophysics