ASCA OBSERVATIONS OF THE CORONAL X-RAY-EMISSION OF ALGOL

We report a 1.7 day ASCA X-ray observation of the 2.87 day binary Algo l (beta Per), centered on the secondary eclipse. Spectra accumulated f or different intensity states show a prominent He-like iron K line at 6.7 keV. A two-temperature variable abundance plasma model applied to the spectra yielded temperatures of similar to 8 and similar to 30 MK. The modeled coronal abundances of Fe, O, Mg, Si, S, Ar, and Ca were a factor of 2-3 below the solar photospheric value, and N < 0.1. These model abundance anomalies are similar to those found from the ASCA spe ctra of other late-type stars and may indicate either true deviations from solar abundances or problems with the assumptions and atomic phys ics of the plasma models. The X-ray light curve shows a factor of 2 in crease in flux over 13 hr beginning in the middle of the secondary ecl ipse, with a shallow eclipse centered on phase 0.45. The orbital light curve is similar to that observed by ROSAT 1 year earlier. The rise i n flux is caused by an increase in the emission measure of the higher temperature component. The intensity variation is not associated with any major change in the abundances or temperature of the two component s.