Effective Temperature-Colour and Surface Brightness-Colour Relationships for the Latest-Type Stars
Abstract
New calibrations of six broad-band optical and near infrared colours (U-B, B-V, V-R, V-I, R-I and V-K) against accurate effective temperatures (T_eff) derived from empirical and semi-empirical (infrared flux) methods for G, K and M giants are presented. Polynomial coefficients for these relationships are given. We also present independent relationships between the visual surface brightness parameter F_V and the colours (V-R), (V-I), (R-I) and (V-K). We find that (U-B) and (B-V) are unsuitable as T_eff indicators. The tightest relationship in each case is found for the (V-K) index. Our mean relationships agree reasonably well with similar relationships derived by other authors, where such are available. These relationships are suitable for use in the determination of spot areas and temperatures in active late-type stars.
- Publication:
-
Irish Astronomical Journal
- Pub Date:
- July 1996
- Bibcode:
- 1996IrAJ...23..177A