Summary: Effective temperature­colour and surface brightness­colour
relationships for the latest­type stars
P.J. Amado and P.B. Byrne
Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland
May 28, 1996
Abstract
New calibrations of six broad­band optical and
near infrared colours (U \Gamma B, B \Gamma V , V \Gamma R,
V \Gamma I, R \Gamma I and V \Gamma K) against accurate effec­
tive temperatures (T eff ) derived from empiri­
cal and semi­empirical (infrared flux) methods
for G, K and M giants are presented. Poly­
nomial coefficients for these relationships are
given. We also present independent relation­
ships between the visual surface brightness pa­
rameter FV and the colours (V \Gamma R), (V \Gamma I),
(R \Gamma I) and (V \Gamma K). We find that (U \Gamma B)
and (B \Gamma V ) are unsuitable as T eff indicators.
The tightest relationship in each case is found
for the (V \Gamma K) index. Our mean relation­

Source: Armagh Observatory

Collections: Physics