A 1.3 MM survey for circumstellar dust around young Chamaeleon objects.

We present the results of the first 1.3 mm continuum survey of young stellar objects in the Chamaeleon I and II dark clouds. 36 objects were observed, including five intermediate-mass stars. We detected emission from about 50% of the sources. At 1.3 mm, none of the sources with a spectral index α(2.2-25 μm) smaller than -1 could be found. There is no correlation between 1.3 mm flux and Hα equivalent width. The detected millimetre radiation is most probably thermal emission from cold circumstellar dust grains.

We combined the measured millimetre fluxes with infrared observations and modelled the broad-band energy distributions by both an exact spherically-symmetric radiative transfer model including scattering and properties of different dust populations and a model for geometrically thin disks with parametrized temperature and density distribution. In this way we were able to constrain the parameters of the emission regions.