X‐Ray Spectroscopic Observations of EX Hydrae and Mass Determination of the White Dwarf

From X-ray line spectroscopy with ASCA , we have measured the temperature of the shock where the accretion flow meets the surface of the white dwarf in the intermediate polar EX Hya to be kT = 15.4 + 5.3 −2.6 keV, and obtained the corresponding white dwarf mass to be 0.48 + 0.10 −0.06 M ☉ . We have found that the abundances of silicon, sulfur, and argon are marginally consistent with solar values (1.3 ± 0.3), while that of iron is significantly smaller (0.6 ± 0.2). Our approach to mass determination is free from uncertainties in the inclination angle of the binary and thus is widely applicable to intermediate polars.