The peculiar X-ray and radio star AS431

During a systematic survey of X-ray flux-limited late-type stars^1,2, we have rediscovered a highly reddened emission-line star, previously listed³ 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. We report here Einstein observations revealing that AS431 has a highly absorbed X-ray spectrum and a relatively strong intrinsic flux of>= 5 × 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), showing that it is also a moderately strong radio source ( ~ 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.