The temperature, luminosity, and spectrum of Kapteyn's star.
Abstract
The temperature of Kapteyn's star, a halo-population subdwarf, has been determined from narrow-band photometry in the near infrared. The color temperature is that of a normal dwarf of type M 1.0, while the TiO strength indicates type M0.0. The effective temperature is estimated to be 3800 K, and the absolute bolometric magnitude is + 9.50. Kapteyn's star lies 1.4 bolometric magnitudes below the mean main sequence for stars in the solar neighborhood. The spectrum of Kapteyn's star has been observed in the blue and red regions with an objective prism. There is no obvious weakening of the atomic lines, but the TiO bands are weak for the atomic-line strength, while the bands of MgH and CaH are greatly enhanced relative to their strength in normal early M dwarfs. Although the metal abundance of Kapteyn's star cannot be determined from the present data, its TiO and CaH band strengths are found to be fairly reliable indicators of its temperature and luminosity, respectively. Subject headings: stars: high-velocity - stars: individual - stars: late-type - stars: subdwarfs
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1976
- DOI:
- 10.1086/154263
- Bibcode:
- 1976ApJ...205..186W