The UBVr colors of extreme Pop II giants.
Abstract
Summary. The UB Colors of Pop II giants with metal abundances 1/100 and 1/1000 times the solar metal abundances are computed. For these stars the Rayleigh scattering is extremely important for the U fluxes. The mean intensity j, the source function for the Rayleigh scattering, has been determined, considering not only the continuous absorption of hydrogen and the metals but also the line absorption. The UBYr colors are given in the range 42000 Teff 77000 and 4.6 < L/L0 < 1800. From this the relation between B - V and Teff is determined for different luminosities and also the ultraviolet excess, which for a given B - V depends on the gravity, g, as well as on the metal abundance Z Key words: colors - Population II giants - Rayleigh scattering - source function
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1973
- Bibcode:
- 1973A&A....24..447B