SUPERSTRONG X-RAY-EMISSION FROM A DEEPLY EMBEDDED YOUNG STELLAR OBJECT IN THE SERPENS CLOUD CORE

We report the ROSAT detection of strong X-ray emission from an optical ly invisible infrared source in the Serpens star forming region. The X -ray source can be identified with the infrared star EC 95, a deeply e mbedded (A(V) approximate to 34 mag) young stellar object. The quiesce nt soft X-ray luminosity of this object is about (6-18) x 10(32) erg/s ec, making it the most X-ray luminous young stellar object ever detect ed. Since this exceeds the quiescent, i.e. non-flaring, X-ray luminosi ty of any known coronal X-ray source by at least about one order of ma gnitude, our result suggests that a non-solar-like origin for the X-ra y emission of EC 95 has to be considered.