VARIABLE RADIO-SOURCES IN THE CORONA AUSTRALIS CLOUD

The radio continuum emission from pre-main-sequence stars in the Coron a Australis star formation region has been studied over the period 198 5-1992 using the Very Large Array (VLA) and the Australia Telescope. O ne source, IRS 5, shows significant long- and short-term variability, while another, Radio Source 5 of Brown [ApJL, 332, L31 (1987)], is pos sibly variable. Radio emission is detected from the T Tauri star S CrA . During 1992 IRS 5 underwent a major radio outburst, when the flux in creased to over ten times its mean quiescent value. During the period of high emission, the Aux was stable over time periods of less than 24 h, in contrast with the radio outburst of another young star, DoAr 21 [Feigelson & Montmerle, ApJL, 289, L19 (1985)]. The spectra of all th ree objects studied appear consistent with a thermal emission process, and that of IRS 1 may be from an optically thick region. (C) 1996 Ame rican Astronomical Society.