Brown Dwarfs in ChaI Dark Cloud

With this method, we identify most of our object candidates as being of spectral type M5 or later. Our results show that there is no strong drop in the number of objects for the latest spectral types, hence brown dwarfs may be as abundant as low-mass stars in this region. Also, both kind of objects have a similar spatial distribution.

We derive an index {alpha}=0.6+/-0.1 of the mass function in this region of dispersed star formation, in good agreement with the values obtained in other star forming regions and young clusters. Some of the brown dwarfs have strong H{alpha} emission, suggesting mass accretion. For objects with published infrared photometry, we find that strong H{alpha} emission is related to a mid-infrared excess, indicative of the existence of a circumstellar disk.