GHRS observations of the white dwarf in U Geminorum

We have observed the dwarf nova U Geminorum while it was in quiescence in t he wavelength range 1162-1448 Angstrom using the GHRS on Hubble Space Teles cope. The time-resolved (lambda/delta lambda = 2000) spectra are dominated by the white dwarf in the system. By analyzing the Doppler shifts of the ph otospheric metal absorption lines that punctuate the spectrum, we have accu rately determined the orbital velocity amplitude of the white dwarf to be 1 07.1 +/- 2.1 km s(-1). For an inclination of 67 degrees and a K-2 velocity of 294.7 km s(-1), this implies a mass of 1.12 and 0.41 M. for the white dw arf and secondary, respectively. A comparison between the integrated spectr um and synthesized spectral models indicates a temperature of similar to 30 ,000 K, consistent with earlier determinations, and an abundance pattern th at is distinctly nonsolar and indicative of CNO processing. Specifically, t he abundance of C appears to be of order 0.1 solar, while N is similar to 4 times solar.