The X-Ray Eclipsing Cataclysmic Variable 1H1752+081

Abstract

The orbital light curve of 1H1752+081 pieced together from the ROSAT All-Sky Survey (RASS) data shows there is considerable variation from orbit to orbit: an orbital hump around phases 0.5–0.9 can be seen. 1H1752+081 was fairly hard (HRl=+0.8) but still showed an unusually high 0.1-3 cts/s in the ROSAT PSPC, making it one of the brightest X-rays sources in the CV sky. We have obtained ROSAT PSPC pointed observations centered on two eclipses on 1993 Sept. 10 and 11. The eclipse of the X-ray ”accretion spot” agrees with the optical eclipse and is total as is expected for the estimated inclination of 80°. The hump at 0.7–1.0 keV in the X-ray spectrum can only be reproduced using fairly ”warm” gas (0.3–1.4 keV) with lots of X-ray emission lines, and the hard emission must be due to a dominant, optically thin ”hot” gas (> 3 keV) component. The X-ray spectrum does not change in shape with orbital phase; particularly, the amount of absorption is constant.