L. Origlia

A search for young stellar objects in southern dark clouds

The IRAS Point Source Catalog has been used to search 482 southern dark clouds for evidence of young stellar objects. Only 6 percent of the selected dark clouds have associated IRAS sources with IRAS colors typical of pre-main-sequence stars. A study of the energy distributions obtained from JHKLM photometry and IRAS flux densities give an identification of these IRAS sources. Thirteen sources have been classified as new low-mass protostellar objects and T Tauri-type stars with nebular surrounding material disks, while four IRAS sources have no evidence of near-IR excesses and appear to be similar to post T Tauri stars in which the nebular disks are probably absent or optically thin. 17 refs.

Dust Envelopes and IR Excesses in a Sample of RS CVn-Type Binaries

In recent years, we have been studying the energy distribution of RS CVn binaries from UV to far IR wave lengths, in order to derive general properties of the systems and to better understand their evolutionary scenario, including the history of mass loss (Busso et al., 1987, 1988). In this framework, we have so far analyzed, at different level of accuracy, a total of about 60 sources, among which 30 have been the object of detailed studies, on the basis of broad band photomertic observations from 0.35 to 60 µm, using ground-based telescopes (mainly at La Silla, ESO) and IRAS-PSC information. For these 30 binaries, the quasi-periodic variations due to the presence of photospheric spots have been carefully subtracted, to derive the energy distributions of the unperturbed systems.

IRAS and Near Infrared Observations of Peculiar Nebulosities

We used the IRAS survey to search for IR emission from 95 peculiar nebulosities with CO emission. Fifty-two IRAS sources are associated with them. We discuss the nature of the sources on the basis of their IRAS color-color diagram and of near-IR observations.