A comparison of DA white dwarf temperatures and gravities from Lyman and Balmer line studies

M. A. Barstow, J. B. Holberg, I. Hubeny, S. A. Good, A. J. Levan, F. Meru

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We present measurements of the effective temperatures and surface gravities for a sample of hot DA white dwarfs, using the Lyman line data available from the HUT, ORFEUS and FUSE FUV space missions. Comparing the results with those from the standard Balmer line technique, we find that there is a general good overall agreement between the two methods. However, significant differences are found for a number of stars, but not always of a consistent nature in that sometimes the Balmer temperature exceeds that derived from the Lyman lines and in other instances it is lower. We conclude that, with the latest model atmosphere calculations, these discrepancies probably do not arise from an inadequate theoretical treatment of the Lyman lines but rather from systematic effects in the observation and data reduction processes, which dominate the statistical errors in these spectra. If these systematic data reduction effects can be adequately controlled, the Lyman line temperature and gravity measurements are consistent with those obtained from the Balmer lines when allowance is made for reasonable observational uncertainties.

Original languageEnglish (US)
Pages (from-to)211-222
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Nov 21 2001


  • Stars: atmospheres
  • Ultraviolet: stars
  • White dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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