Detection of soft X-rays from alpha Lyrae and eta Bootis with an imaging X-ray telescope.
Abstract
Results are presented for observations of Alpha Lyr (Vega) and Eta Boo with an imaging X-ray telescope during two rocket flights. It is found that Vega and Eta Boo are soft X-ray sources with respective luminosities of approximately 3 x 10 to the 28th erg/s (0.15-0.8 keV) and 1 x 10 to the 29th erg/s (0.15-1.5 keV). Surface X-ray luminosities of about 640,000 erg/sq cm per sec for Vega and 300,000 erg/sq cm per sec for Eta Boo are estimated and shown to fall within the range of solar coronal X-ray emission. It is concluded that in view of the substantially larger surface areas of these stars, the relatively large total soft X-ray luminosity (as compared with that of the sun) can in both cases be understood as resulting from a moderately active corona, although the Vega observation is in severe conflict with simple models for X-ray emission from single main-sequence stars.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1979
- DOI:
- 10.1086/157000
- Bibcode:
- 1979ApJ...229..661T
- Keywords:
-
- Coronas;
- Early Stars;
- Ubv Spectra;
- X Ray Sources;
- Solar X-Rays;
- Stellar Luminosity;
- Stellar Mass Ejection;
- Stellar Models;
- Stellar Winds;
- X Ray Telescopes;
- Astronomy;
- Stellar Coronae:X Rays