An extremely X-ray luminous proto-Herbig Ae/Be star in the Serpens star forming region
Abstract
We present near-infrared spectra for the highly obscured, optically invisible young stellar object EC 95 in the Serpens molecular cloud, from which we recently could detect strong X-ray emission with ROSAT. Its location in the HR diagram suggests this object to be an extremely young ( ~ 2 x 10(5) yr old) intermediate-mass ( ~ 4;M_sun) star, which is most likely the progenitor of a B-type or early A-type main sequence star. The only reasonable explanation for its extremely strong X-ray emission (L_X ~ 1.2 x 10(33) erg/sec) seems to be coronal, i.e. magnetic activity; this view is also supported by the strong radio emission of EC 95. This is quite surprising, since one usually does not expect a magnetic field on intermediate-mass stars, which are thought to lack surface convection zones, the prerequisite for a solar-like dynamo effect. A possible explanation might be that EC 95 currently goes through a short period of deuterium shell burning, which causes convection near the stellar surface and might give rise to a dynamo effect and a corona. Mainly based on observations collected at the United Kingdom Infrared Telescope, Hawaii, USA
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1999
- Bibcode:
- 1999A&A...345..583P
- Keywords:
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- STARS: CORONAE;
- STARS: INDIVIDUAL: EC 95: J182958+011247;
- STARS: INDIVIDUAL: EC 95: J182958+011252;
- STARS: MAGNETIC FIELDS;
- STARS: PRE-MAIN SEQUENCE;
- X-RAYS: STARS