Small Magellanic Cloud Be stars: colour-magnitude relations and mass-loss

Abstract

We present an analysis of optical lightcurves of Small Magellanic Cloud Be-type stars. Observations show that (1) optical excess flux is correlated with near-IR excess flux indicating a similar mechanism and (2) the lightcurves can trace out ``loops'' in a colour-magnitude diagram. A simple model for the time dependent bound-free and free-free emission produced by an outflowing circumstellar disk gives reasonable fits to the observations.

2 pages - Conference proceedings to 'Mass Loss from stars and the evolution of stellar clusters' - Lunteren, The Netherlands, May 29 - June 1, 2006. A. de Koter, L. Smith & R. Waters