ASCA Observations of the Chamaeleon II Dark Cloud

ASCA results of eight X-ray sources in the Chamaeleon II dark cloud are presented. Six sources were identified as low-mass young stellar objects, either Class II–III sources or T Tauri stars with X-ray temperatures and luminosities in the range of 0.8–3 keV and 10^29.9–10^31.1 erg s⁻¹, respectively. Two of them showed time variability: one with typical flare profile and the other with a light curve showing fast-rise and gradual decay. These variable sources exhibited a higher temperature than did those of the other sources with less time variability. We found a high-temperature, time-variable, and moderately absorbed X-ray source which has no cataloged counterpart at any other wavelength. We also found hard X-rays at the position of a Herbig Ae candidate with an extremely large NH of 2×10²³ H cm⁻², one order of magnitude higher than that estimated from the optical extinction. The origin of the X-rays, including these two sources, are discussed.