The peculiar X-ray and radio star AS431

The authors have rediscovered a highly reddened emission-line star, previously listed as AS431, which sheds light on whether both radio and X-ray emission from the winds of very hot stars can be non-thermal in origin. Einstein observations reveal that AS431 has a highly absorbed X-ray spectrum and a relatively strong intrinsic flux of >=5 x 10-12 erg cm-2 s-1, and observations at 20 cm and 6 cm with the National Radio Astronomy Observatory Very Large Array (VLA), that is is also a moderately strong radio source (approx. 35 mJy). These data, together with optical and infrared observations, suggest a model in which both the radio and X-ray emissions arise in a chaotic stellar wind emerging from a single luminous Wolf-Rayet star. (author)