Soft coronal X-rays from β Pictoris
arXiv:1203.3242 · doi:10.1088/0004-637X/750/1/78
Abstract
A type stars are expected to be X-ray dark, yet weak emission has been detected from several objects in this class. We present new Chandra/HRC-I observations of the A5 V star β Pictoris. It is clearly detected with a flux of 9+-2 10^{-4} counts/s. In comparison with previous data this constrains the emission mechanism and we find that the most likely explanation is an optically thin, collisionally dominated, thermal emission component with a temperature around 1.1 MK. We interpret this component as a very cool and dim corona, with \log L_X/L_{bol}=-8.2 (0.2-2.0 keV). Thus, it seems that β Pictoris shares more characteristics with cool stars than previously thought.
accepted by ApJ, 5 pages, 2 figures