A STUDY OF THE CHAMELEON-I DARK CLOUD AND T-ASSOCIATION .5. LUMINOSITY FUNCTION FOR MEMBERS

We have compiled a list of 81 probable members in the Chamaeleon I star forming region. New ground-based infrared photometry is presented and infrared spectral energy distributions (SEDs) are constructed by combining ground-based and IRAS data. Classification based on the spectral slope of the SEDs between 2.2 and 25-mu-m indicates that Chamaeleon I is on the average in a later stage of evolution than the rho Ophiuchi cluster. Having extended the SEDs to shorter wavelengths by including results from optical photometry published in the literature, we deduced bolometric luminosities for 62 objects. The resulting luminosity function (LF) of Chamaeleon I is very similar to that of Taurus. We cannot detect the segregation between embedded and visible objects observed in the LF of the rho Ophiuchi cluster. In order to gain a qualitative understanding of this difference, we propose a scenario in which the most massive subregions of clumpy molecular clouds start producing stars before the smaller ones.