Population studies. I. The Bidelman-MacConnell "weak-metal" stars.
Abstract
BVRI and DDO photometry together with kinematic data are presented for the spectroscopically chosen sample of Bidelman-MacConnell (BM) "weak-metal" stars. Analysis yields chemical abundances and space motions, which are compared with those of the kinematically selected sample of Eggen, Lynden-Bell, and Sandage (ELS). The BM sample appears to contain a significant proportion of low-abundance, low-eccentricity objects, in contrast to the results of ELS (≡ 20% of BM objects with [Fe/H] ≤ -1 have e ≤ 0.4). The velocity dispersion of such stars perpendicular to the galactic plane is 60±9 km s-1. Finally, for stars with [Fe/H] ≤ -1.2 the velocity ellipsoid is described by σu = 125±11, σv = 96±9, σw = 88±7 km s-1.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- July 1985
- DOI:
- 10.1086/191049
- Bibcode:
- 1985ApJS...58..463N
- Keywords:
-
- Metallicity;
- Milky Way Galaxy;
- Star Distribution;
- Stellar Composition;
- Stellar Motions;
- Stellar Spectrophotometry;
- Dwarf Stars;
- Eccentricity;
- Galactic Evolution;
- Giant Stars;
- Globular Clusters;
- Horizontal Branch Stars;
- Radial Velocity;
- Stellar Orbits;
- Astronomy