Mass flow in the O7f binary UW Canis Majoris.
Abstract
The ultraviolet spectrum of the eclipsing binary UW CMa (O7f + 0-B) has been observed by the Princeton telescope spectrometer on the Copernicus satellite in the wavelength region from about 560 A at a resolution corresponding to 0.2 A. A number of stellar and interstellar lines appear in the spectrum. The following lines showing P Cygni characteristics have been observed: C iii (977, 1175 A), S iv (1062, 1072 A), P V (1117 A), Fe iii + Si iv? (1122 A), P V + Si iv? (1128 A), N V (1238, 1242 A), Si iv (1393, 1402 A), and C iv (1549 A). The centers of the absorption components of the P Cygni lines yield radial velocities of from -200 to -800 km 1, while the peaks of the emission components are shifted by +400 to +800 km s These velocities are significantly larger than the projected orbital velocity of about 200 km 1, and indicate that gas motions in the system are occurring. A mass-loss rate of about 3 10 - 6 solar masses per year is estimated. A few photospheric absorption lines from the 07f component are also present: N 111(1006, 1183, 1184 A) and possibly He 11(1084 A). A discussion of the evolution of this system, based on the current observations as well as earlier ground-based spectroscopic and photometric investigations, is given. Subject headings: eclipsing binaries - mass loss - Of-type stars - stars, individual
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1975
- DOI:
- 10.1086/153927
- Bibcode:
- 1975ApJ...201..607M
- Keywords:
-
- Eclipsing Binary Stars;
- O Stars;
- Stellar Mass Ejection;
- Ultraviolet Spectra;
- Absorption Spectra;
- Emission Spectra;
- Far Ultraviolet Radiation;
- Line Spectra;
- Radial Velocity;
- Stellar Spectra;
- Astrophysics