On the Nature of the Dwarf Carbon Star G77-61
Abstract
A variety of new astrometric, photometric, and spectrophotometric data are presented for the low-luminosity carbon star G77-61. The improved parallax yields Mv = +10.08±0.43, while the revised temperature estimate from infrared, optical, and ultraviolet fluxes in 4100 (+200, -300)K, yielding logL/L_sun; = -1.75±0.16. Most importantly, radial velocity variations have been detected, with the binary period 245 days. The unseen companion probably is a cool white dwarf of much higher mass than the visible object. Both the spectrum and the H-R diagram position below the main sequence require G77-61 to be either extremely metal poor, or helium enriched and at least moderately metal poor.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1986
- DOI:
- 10.1086/163805
- Bibcode:
- 1986ApJ...300..314D
- Keywords:
-
- Binary Stars;
- Carbon Stars;
- Dwarf Stars;
- Stellar Composition;
- Stellar Evolution;
- Stellar Spectrophotometry;
- Astrometry;
- Cool Stars;
- Hertzsprung-Russell Diagram;
- Radial Velocity;
- Spectral Energy Distribution;
- Stellar Mass Accretion;
- Stellar Motions;
- Astrophysics;
- STARS: ABUNDANCES;
- STARS: BINARIES;
- STARS: CARBON;
- STARS: INDIVIDUAL ALPHANUMERIC: G77-61