Automated classification of variable stars for ASAS 1-2 data

摘要

With the advent of surveys generating multi-epoch photometry and thediscovery of large numbers of variable stars, the classification of these starshas to be automatic. We have developed such a classification procedure forabout 1700 stars from the variable star catalogue of ASAS 1-2 (All SkyAutomated Survey, Pojmanski 2000) by selecting the periodic ones and byapplying an unsupervised Bayesian classifier using parameters obtained througha Fourier decomposition of the light curve. For irregular light curves we usedthe period and moments of the magnitude distribution for the classification. Inthe case of ASAS 1-2, 83% of variable objects are red giants. A generalrelation between the period and amplitude is found for a large fraction ofthose stars. The selection led to 302 periodic and 1429 semi-periodic starswhich are classified in 6 major groups: eclipsing binaries, "sinusoidalcurves", Cepheids, small amplitude red variables, SR and Mira stars. The typeclassification error level is estimated to be about 7%.