Hubble Space Telescope observations of the dwarf nova WZ Sagittae: A very rapidly rotating white dwarf

We present Hubble Space Telescope Goddard High-Resolution Spectrograph G140L spectra of the white dwarf in WZ Sge, exposed during quiescence. Our best-fitting synthetic spectra yield a rapidly rotating white dwarf with velocity V-rot sin i = 1200(-400)(+300) km s(-1), white dwarf effective temperature T-wd = 14,800 K the gravity log g = 8.0, and the chemical abundances relative to solar in number (with 3 sigma error bars) of C, 5.0(-2.0)(+2.0); N, 3.0(-1.0)(+1.0); and Si, <0.1. We also reexamined a previous Hubble Space Telescope Faint Object Spectrograph G130H spectrum reported by Sion and coworkers and obtained consistent values, but lower C and N abundances. We do not detect a measurable systematic shift in our observed spectra, presumably due to the extremely low mass of the companion.