Mode Identification in Pulsating White Dwarfs Using the HST
Kepler, S. O.; Clemens, J. C.; Jiang, X. J.; Koester, D.; Robinson, E. L.; Nather, R. E.
Brazil, United States, Germany, China
Abstract
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 the ultraviolet just as the theoretical models predict for l=1 modes. We do not find any pulsation mode visible only in the ultraviolet, as expected if high l=l pulsations were excited.