Fases de actividad y quietud en estrellas Be de cumulos abiertos galacticos: una mirada con WISE

Abstract

WISE (Wide-Field Infrared Survey Explorer) photometry is very useful for studying known Be stars from open clusters, and also detect new Be candidates that can then be studied spectroscopically. Through the modelling of near infrared photometry of star plus disc systems with Bedisk/Beray codes, we adequately describe the photometric characteristics of Be stars in seventeen galactic open clusters with ages between 10 and 100 Myr. The location of the stars Be in WISE colour-magnitude and colour-colour diagrams, permits the classification in two groups: active stars (those that are surrounded by a developed disc) and quiescent objects (in a stage without a detectable disk). This allows us to study how often Be stars are in these different phases. We find that about half of the Be stars in the studied clusters are in an active phase, and that this fraction it is dependent on the spectral type. The location of the stars with a disc developed in the colour diagram magnitude requires mass loss rates that are in accordance with expected values for stellar models in rapid rotation.