Luminosities, colors, and motions of the brightest A-type stars
Abstract
Colors and magnitudes on the (U,B,V) system for the stars of spectral type B8 or later and B- V <$0.3, with visual magnitude brighter than 5.5, are listed in Table I. The colors of the B8 to A0 main sequence stars outline an area of minimum absorption near the sun that extends approximately 100 parsecs in the center (galactic) and anticenter directions but less than half that distance in the rotation and antirotation directions. The space motions of the stars of known luminosity indicate that the A-type objects consist mainly of members of a half-dozen stellar groups. The distribution of the members of some of these groups in the color luminosity array suggests that the evolution of the A-type stars may be through the region of the Ap stars and F-type giants and into the red giant region after passing the "Hertzsprung gap" as Scuti variables. The Hyades and Pleiades groups probably contain stars with a considerable range in age. At least 50 % of the A-type stars are probably members of binary systems.
- Publication:
-
The Astronomical Journal
- Pub Date:
- November 1963
- DOI:
- 10.1086/109198
- Bibcode:
- 1963AJ.....68..697E