What we learn from quantitative ultraviolet spectroscopy of naked white dwarfs in cataclysmic variables

Using the Hopkins Ultraviolet Telescope and Hubble Space Telescope, observe rs have now obtained UV spectra with sufficient signal to noise and resolut ion to allow quantitative spectroscopic analyses of the WDs in several DNe. In the "cleanest" DNe, such as U Gem, the observations are allowing the ba sic physical parameters of the WD - temperature, radius, gravity, rotation rate, and surface abundances - to be established. A second component also e xists in these systems, which may either be the disk or may be related to t he WD itself. Here I summarize the current state of the observations and ou r understanding of the data, highlighting some of the uncertainties in the analyses as well the prospects for fundamentally advancing our understandin g of DNe and WDs with future observations. (C) 2000 Elsevier Science B.V. A ll rights reserved.