M Subdwarf Secondaries: A Test of the Metallicity Scale
Abstract
We present spectra of three M subdwarfs which are common proper motion companions to F or G subdwarfs of known metallicity. The assumption that the companions have the same composition allows us to test the Gizis (1997, AJ, 113, 806) M subdwarf classification system and its correspondence to metallicity. The results are in excellent agreement with the Gizis (1997) scale, thereby showing that the Allard & Hauschildt (1995, \apj, 445, 433) Extended model atmospheres agree well in the 6200 -- 7400 Angstroms region for cool metal-poor stars. We also show that the results are consistent with the main sequences of globular clusters using the Reid (1997, AJ, in press) distance scale. (SECTION: Stars)
- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- November 1997
- DOI:
- 10.1086/134000
- arXiv:
- arXiv:astro-ph/9708244
- Bibcode:
- 1997PASP..109.1233G
- Keywords:
-
- SUBDWARFS;
- GALAXY: EVOLUTION;
- STARS: ABUNDANCES;
- Astrophysics
- E-Print:
- 10 pages, 3 figures, AASTeX, to appear in the November 1997 PASP