Observations of proper-motion stars. II.
Abstract
In the course of an observational program on white dwarfs, results of which have been reported earlier in Paper I, colors and spectra of many non-white dwarfs were obtained. A few wide binaries are found to be optical pairs only and the data for these pairs are given in Table 1. New physical pairs containing white dwarfs were established, and new single white dwarfs were discovered spectroscopically and are listed in Table 2. This paper lists twelve newly observed white dwarfs of spectral types DA and DF and gives further observations on two stars from our earlier work. The RR Lyr variable, AP Ser, is also a visual binary. Photometric observations of the faint, physical companion give (U - B) = +0.12 and lead to a luminosity of My = + 1.6 at median light of the variable. Stars found not to be white dwarfs during our earlier survey of proper-motion stars are listed in Table 3. Lowell survey colors were also studied statistically and found to be moderately reliable. Propermotion stars of color class -1 and most of those of color class 0 are almost certainly white dwarfs. Also, some interesting subdwarf M stars were found, with weak TiO and strong MgH bands.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1965
- DOI:
- 10.1086/148362
- Bibcode:
- 1965ApJ...142..925E