X-Ray Sources in Regions of Star Formation. VI. The R CRA Association as Viewed by Einstein.
Abstract
We report on optical identifications of X-ray sources in the vicinity of the R CrA association. We identify 11 low-mass pre-main-sequence stars as counterparts of 9 X-ray sources. We also find X-ray emission from coordinates consistent with the position of 3 bright late-B stars, although the emission may come from lower mass companions. The X-ray-selected stars lie along a narrow locus in the luminosity-temperature diagram at an age of about 7 Myr, which is considerably older than the estimated ages of the higher mass stars or of the IR-excess stars. We determine the physical characteristics of these stars, including masses, ages, and Lithium abundances. We estimate that the complete membership of the R CrA association amounts to about 90 stars, mostly older naked T Tauri stars, and that the population is consistent with the standard IMF.
- Publication:
-
The Astronomical Journal
- Pub Date:
- October 1997
- DOI:
- 10.1086/118584
- arXiv:
- arXiv:astro-ph/9707083
- Bibcode:
- 1997AJ....114.1544W
- Keywords:
-
- STARS: PRE-MAIN SEQUENCE;
- X-RAYS: ISM;
- Astrophysics
- E-Print:
- LATEX text (aaspp4 style) and 7 postscript figures. Accepted for publication in the Astronomical Journal, October 1997. Also available by anonymous ftp to sbast3.ess.sunysb.edu (cd pub/fred