X-Ray Astronomy in the Exosat Era: Proceedings of the XVIII Eslab Sysmposium, Held in the Hague, the Netherlands, 5-9 November 1984 (Softcover ReprintPaperback - Softcover Reprint of the Original 1st 1985, 2 October 2011
Algol is a triple system containing a 70 hr eclipsing binary (K IV and
B8 V) in a 694 day orbit with an A V star. The X-ray emission from this
system (Schnopper et al 1976) is thought to be associated with a corona
surrounding the lobe filling and synchron- ously rotating K IV star.
This is based on the similarity of the X-ray spectrum and luminosity of
this system to that of the RS CVn binaries which also contain K
sub-giants with similar rotation periods and the fact that the
luminosity of any coronae surrounding the B8 V and AV companion stars
should not be enhanced by rapid rotation (Pallavicini et al 1980, White
et al 1980). The Einstein SSS measurement showed the X-ray spectrum to
be two component with 6 7 temperatures of 7. 10 K and 3. 10 K (White et
al. 1980). As dis- cussed by Swank et al. (1981), the problem in
understanding stellar coronae in general is how to scale up the solar
model to account for the enhanced luminosities. The close to 900
inclination and similar sizes for the Band K stars of 3. 6 and 3. 8 R0
respectively make Algol an ideal candidate for an X-ray eclipse
measurement wherein the size of the X-ray emitting coronal structures
can be directly measured. In this paper we report a continuous
observation through the secondary eclipse of Algol using the EXOSAT
Observatory. 2.