X-Ray Sources in Regions of Star Formation. II. The Pre--Main-Sequence G Star HDE 283572
Roth, M.; Linsky, J. L.; Walter, F. M.; Carrasco, L.; Brown, A.; Imhoff, C. L.; Rydgren, A. E.; Vrba, F.; Chugainov, P. F.; Shakovskaya, N. I.
United States
Abstract
This paper reports the detection of HDE 283572, a ninth-magnitude G star 8 arcmin south of RY Tau, as a bright X-ray source. The observations reveal this object to be a fairly massive (about 2 solar masses) pre-main-sequence star associated with the Taurus-Auriga star formation complex. It exhibits few of the characteristics of the classical T Tauri stars and is a good example of a 'naked' T Tauri star. The star is a mid-G subgiant, of about three solar radii and rotates with a period of 1.5 d. The coronal and chromospheric surface fluxes are similar to those of the most active late type stars (excluding T Tauri stars). The X-ray and UV lines most likely arise in different atmospheric structures. Radiative losses are some 1000 times the quiet solar value and compare favorably with those of T Tauri stars.