Soft Coronal X-Rays from β Pictoris
Schmitt, J. H. M. M.; Robrade, J.; Günther, H. M.; Drake, J. J.; Wolk, S. J.; Lisse, C. M.
United States, Germany
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-1. 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 LX /L bol = -8.2 (0.2-2.0 keV). Thus, it seems that β Pictoris shares more characteristics with cool stars than previously thought.