HST/STIS Spectroscopy of the Intermediate Polar EX Hydrae

W e presentthe resultsofouranalysisofsix orbitsof HST/STIS tim e-tagged spectroscopy ofthe interm ediate polar,EX H ydrae. The high tim e and wavelength resolution of the HST/STIS spectra provided an excellent opportunity to study the U V properties ofEX H ya. M easurem ents ofthe continuum and em ission line (cid:13)uxes corroborate earlier studies that show that the em ission line (cid:13)uxes are m odulated m ore strongly than the continuum (cid:13)ux and originate from the accretion curtains,while the continuum (cid:13)ux originatesfrom the white dwarf photosphere. The m easured K am plitude ofthe narrow em ission line radialvelocity curve isused to calculate a white dwarfm assof0 : 91 (cid:6) 0 : 05 M (cid:12) .Synthetic white dwarfphotosphere and accretion disk spectralm odels are used to further re(cid:12)ne the white dwarfand accretion disk properties.U sing the spectralm odels, it is determ ined that EX H ya has a white dwarfofm ass 0 : 9 M (cid:12) , T = 23000 K , an accretion disk truncated at2 : 5 R W D ,and isata distance of60 pc.