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Mode Identification of BPM 37093 with the HST

Kepler, S. O.; Montgomery, M. H.; Winget, D. E. +3 more

Theoretical calculations indicate that the massive pulsating white dwarf BPM 37093 has a crystallized interior (Winget et al. 1997, Kanaan 1996, Montgomery 1998). Crystallization was predicted theoretically about 40 years ago (Abrisokov 1961, Kirshnitz 1960; Salpeter 1961), but in spite of its importance in astrophysics, there is no direct observa…

Mode Identification in Pulsating White Dwarfs Using the HST

Kepler, S. O.; Clemens, J. C.; Jiang, X. J. +3 more

We obtained time-resolved ultraviolet spectroscopy for the pulsating DA stars G 226-29 and G 185-32 and for the pulsating DBV star PG 1351+489 with the Hubble Space Telescope Faint Object Spectrograph, to compare the ultraviolet to the optical pulsation amplitudes. We find that for essentially all observed pulsation modes the amplitude rises to th…

The Temperature of the Hot DB GD 190

Provencal, J. L.; Shipman, H. L.

We are currently in the midst of an investigation of hydrogen and carbon abundances in hot DB white dwarfs. Our HST UV spectra give evidence that hot DBs contain traces of carbon which can be used to determine the temperatures of these objects. We present the results of our investigation of GD 190.