EXOSAT observations of three DA white dwarfs.
Beuermann, K.; Giommi, P.; Koester, D.; Thomas, H. -C.; Graser, U.; Tagiaferri, G.
United States, Germany, Netherlands
Abstract
Exosat broad band filter observations, optical and IUE spectra, are presented for three DA white dwarfs. One source is a previously known Hyades white dwarf, the other two are new DA detected by Exosat. The results are consistent with previous observations of other DA white dwarfs and indicate that an absorber other than hydrogen (most probably helium) is present in the photosphere of these objects. From the present data, however, a distinction between the two possibilities (homogeneous vs stratified) is not possible.