Temperatures for Hot and Pulsating DB White Dwarfs Obtained with the IUE Observatory
Hansen, C. J.; Winget, D. E.; Green, Richard F.; Fontaine, G.; Sion, Edward M.; Wesemael, F.; Liebert, James; Shipman, Harry L.
United States, Canada
Abstract
Ultraviolet energy distributions are presented for 12 hot, helium-atmosphere DB white dwarfs, including the four known pulsating stars which define an empirical DB instability strip. Temperatures are derived exclusively from fits to the ultraviolet energy distributions, especially in the λλ1200 - 2000 region which is most sensitive to temperature. Comparison is made between fits using various atmospheric models and with temperatures derived from optical observations. Uncertainties due to the model atmospheres, the IUE observations, and interstellar reddening are discussed.