Population Studies. II. Kinematics as a Function of Abundance and Galactocentric Position for [Fe/H]<=-0.6
Abstract
A catalog is presented of some 1200 Galactic objects which have radial velocities and (Fe/H) abundances of -0.6 or less. These data are analyzed to yield information on the kinematic properties of the older populations of the Galaxy and on the interdependence between kinematics and abundance. It is found that the kinematics of the available kinematically selected stars differ from those of the nonkinematically selected objects. No evidence is found for any significant difference in the kinematic properties of the various halo subgroups, nor for any dependence of kinematics on abundance. While the rotation of the halo is small at about 37 km/s for (Fe/H) of -1.2 or less, it rises quickly for higher abundances to a value of about 160 km/s at (Fe/H) = 0.6. Objects in the abundance range -0.9 to -0.6 appear to belong predominantly to a population possessing the kinematic characteristics of a thick disk. The implications of these findings for the suggestion that globular clusters belong to the same population as the noncluster objects, for the origin of the thick disk, and for the mass of the Galaxy are discussed.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- August 1986
- DOI:
- 10.1086/191128
- Bibcode:
- 1986ApJS...61..667N
- Keywords:
-
- Abundance;
- Astronomical Catalogs;
- Galactic Nuclei;
- Helium;
- Iron;
- Radial Velocity;
- Milky Way Galaxy;
- Star Distribution;
- Stellar Motions;
- Stellar Rotation;
- Astrophysics;
- GALAXIES: INTERNAL MOTIONS;
- GALAXIES: MILKY WAY;
- STARS: ABUNDANCES;
- STARS: HIGH-VELOCITY;
- STARS: POPULATION II;
- STARS: STELLAR DYNAMICS