A Study of the Spatial and Spectral Characteristics of the Corona of AR Lacertae
Abstract
X-ray observations of the eclipsing RS CVn binary AR Lac covering both primary and secondary minimum, obtained with the position sensitive proportional counter (PSPC) on-board ROSAT, are presented. The X-ray light curves clearly show a deep primary eclipse in all three PSPC spectral bandpasses covering the bands 0.1-0.28 keV, 0.4-1.1 keV, and 1.1-2.4 keV. A shallow secondary minimum occurring before phase 0.5 is seen in the total light curve. Phase-dependent spectral analysis is performed both with a two-temperature model as well as a hydrostatic loop model. During primary eclipse the emission measures of the low- and the high-temperature component drop, while the derived coronal temperatures show no orbital variation. The mean temperature values are 3 x 10 exp 6 K and 14 x 10 exp 6 K, respectively; in the context of the hydrostatic loop model, we find peak loop temperatures of 3.5 x 10 exp 7 K. In order to localize the X-ray emitting regions on the stellar surfaces, a coronal emission region modeling is performed. Two best-fit models are obtained; both models require one prominent coronal feature on each star, a compact structure on the G star, and a more extended structure associated with the K star.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1993
- DOI:
- 10.1086/173039
- Bibcode:
- 1993ApJ...413..710O
- Keywords:
-
- Binary Stars;
- Light Curve;
- Stellar Coronas;
- X Ray Spectra;
- Rosat Mission;
- Spectrum Analysis;
- Stellar Models;
- X Ray Astronomy;
- Astrophysics;
- STARS: BINARIES: ECLIPSING;
- STARS: CORONAE;
- STARS: INDIVIDUAL CONSTELLATION NAME: AR LACERTAE;
- X-RAYS: STARS