Einstein X-ray survey of the Pleiades : the dependence of X-ray emission on stellar age.
Abstract
The data obtained with two pointed observations of 1 deg by 1 deg fields of the Pleiades region have been analyzed, and the results are presented. The maximum-likelihood X-ray luminosity functions for the Pleiades G and K stars in the cluster are derived, and it is shown that, for the G stars, the Pleiades X-ray luminosity function is significantly brighter than the corresponding function for Hyades G dwarf stars. This finding indicates a dependence of X-ray luminosity on stellar age, which is confirmed by comparison of the same data with median X-ray luminosities of pre-main sequence and local disk population dwarf G stars. It is suggested that the significantly larger number of bright X-ray sources associated with G stars than with K stars, the lack of detection of M stars, and the relatively rapid rotation of the Pleiades K stars can be explained in terms of the onset of internal differential rotation near the convective envelope-radidative core interface after the spin-up phase during evolution to the main sequence.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1985
- DOI:
- 10.1086/163143
- Bibcode:
- 1985ApJ...292..172M
- Keywords:
-
- Pleiades Cluster;
- Spaceborne Astronomy;
- Star Clusters;
- X Ray Sources;
- Astronomical Catalogs;
- Dwarf Stars;
- G Stars;
- Heao 2;
- K Stars;
- Stellar Luminosity;
- Stellar Rotation;
- Astrophysics