The Baade-Wesselink Method and the Distances to RR Lyrae Stars. III. The Field Star SW Draconis
Abstract
The authors have obtained simultaneous BV and JHK photometry and radial velocities of typical accuracies of 1 km s-1 for the moderately metal-rich ([Fe/H] ≈ -0.75) RRab star SW Draconis. They have used these data and the surface brightness variation of the Baade-Wesselink method to derive <MV> = +0.94±0.15 mag for this star. The phasing problem encountered earlier recurs for SW Dra when the B-V index is employed. The authors find that SW Dra is only 0.06±0.10 mag fainter than the very metal-poor ([Fe/H] ≈ -2.2) star X Ari, so that the two stars have essentially the same luminosity within the uncertainty despite their large differences in metallicity.The implication of this result upon the derived ages of globular clusters is discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1987
- DOI:
- 10.1086/165090
- Bibcode:
- 1987ApJ...314..605J
- Keywords:
-
- Metallic Stars;
- Stellar Spectrophotometry;
- Variable Stars;
- Globular Clusters;
- Metallicity;
- Radial Velocity;
- Stellar Color;
- Stellar Luminosity;
- Stellar Temperature;
- Astrophysics;
- STARS: INDIVIDUAL CONSTELLATION NAME: SW DRACONIS;
- STARS: LUMINOSITIES;
- STARS: PULSATION;
- STARS: RR LYRAE