Stellar population samples at the galactic poles. III. UBVRI observations of proper motion stars near the south pole and the luminosity laws for the halo and old disk populations.
Abstract
Some 1200 UBV and 650 R, I observations of 1050 stars, mostly with annual proper motion greater than , brighter than visual magnitude 15, and within 100 of the south galactic pole, are presented and discussed. The M-type stars (B - V> +1.15 mag) in the sample are discussed in a current article in The Astrophysical Journal, Part I. The bluer stars indicate that (1) the slopes of the luminosity laws for old disk and halo stars are fairly simllar to Mv near +6 mag, (2) the old-disk-population law has an inflection point near Mv = +7 mag, (3) the halo-population law may peak near Mv = +9 mag on a broad plateau that continues to beyond + 10 mag and drops to zero near +13 mag, and (4) the upper limit for the mass density of the halo population near the Sun is near 9 x 10- M0 pc - 3. Many stars of particular interest in the sample are briefly discussed. These include several possible red subluminous stars, one of which may be a very close solar neighbor; some halo-population giants; and one unique flare star with an amplitude near 0.SmaginR. Subject headings: galaxies: structure - stars: faint blue - stars: proper motion - stars: stellar statistics
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- March 1976
- DOI:
- 10.1086/190366
- Bibcode:
- 1976ApJS...30..351E
- Keywords:
-
- Galactic Structure;
- Milky Way Galaxy;
- Star Distribution;
- Stellar Luminosity;
- Tables (Data);
- Ubv Spectra;
- Giant Stars;
- Halos;
- M Stars;
- Stellar Motions;
- Stellar Spectrophotometry;
- Astronomy