A STUDY OF THE STELLAR POPULATION IN THE CHAMELEON DARK CLOUDS

In this paper we discuss the properties of the stellar population in the Chamaeleon dark clouds. Spectral energy distributions, based on the extant photometric and spectroscopic data base and IRAS fluxes measured from co-added data taken at the position of each star, and spectral types allow placement of the stars in an H-R diagram. The age and mass distributions and the luminosity function for the Chamaeleon stars are compared to those in the Taurus-Auriga dark clouds and are found to be similar. A small subsample (eight of 36) of the Chamaeleon stars show unusual spectral energy distributions which seem best interpreted as arising from circumstellar disks whose inner regions (R(in) < 30-50 R*) are devoid of material. The X-ray properties of this sample of pre-main-sequence objects are compared to those of other pre-main-sequence samples, as well as to the Hyades and the Pleiades main-sequence stars. It is found that the radius of the star plays the primary role in establishing the X-ray luminosity, while the rotation period plays the dominant role in determination of the X-ray surface flux.