S.L. Skinner (Univ. of Colorado), K.R. Briggs, M. Guedel (Paul Scherrer Inst., Switz.)
FU Orionis objects (FUors) are a remarkable class of low-mass pre-main sequence stars that are undergoing disk accretion at high rates. Classical FUors are distinguished by dramatic optical outbursts that last for decades and are attributed to an increase in the disk accretion rate. FUors have been extensively studied in the optical, but X-ray data are lacking. We present first results of an X-ray survey of classical FUors conducted with XMM-Newton. The objectives are to determine if FUors are X-ray sources and to identify plausible emission mechanisms, distinguishing between soft emission from accretion shocks and harder emission that is usually associated with magnetic processes. We have detected the prototype of the class, FU Ori, but the FUor V883 Ori was not detected. The emission of FU Ori is hard and heavily absorbed with a characteristic temperature in excess ~3 keV. Such high-temperature plasma indicates that the X-ray emission of FU Ori is dominated by magnetic processes.
This work was supported by NASA GSFC grant NNG04GH23G.
Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.