Multiwavelength observations of GD 394 Virtual Observatory Resource

Authors
  1. Wilson D.J.
  2. Gansicke B.T.
  3. Koester D.
  4. Toloza O.
  5. Holberg J.B.,Preval S.P.
  6. Barstow M.A.
  7. Belardi C.
  8. Burleigh M.R.
  9. Casewell S.L.,Cauley P.W.
  10. Chote P.
  11. Farihi J.
  12. Hollands M.A.
  13. Long K.S.
  14. Redfield S.
  15. Published by
    CDS
Abstract

We present new Hubble Space Telescope (HST) ultraviolet and ground-based optical observations of the hot, metal-rich white dwarf GD 394. Extreme-ultraviolet (EUV) observations in 1992-1996 revealed a 1.15d periodicity with a 25 per cent amplitude, hypothesized to be due to metals in a surface accretion spot. We obtained phase resolved HST/Space Telescope Imaging Spectrograph high resolution far-ultraviolet spectra of GD 394 that sample the entire period, along with a large body of supplementary data. We find no evidence for an accretion spot, with the flux, accretion rate, and radial velocity of GD 394 constant over the observed time-scales at ultraviolet and optical wavelengths. We speculate that the spot may have no longer been present when our observations were obtained, or that the EUV variability is being caused by an otherwise undetected evaporating planet. The atmospheric parameters obtained from separate fits to optical and ultraviolet spectra are inconsistent, as is found for multiple hot white dwarfs. We also detect non-photospheric, high ionisation absorption lines of multiple volatile elements, which could be evidence for a hot plasma cocoon surrounding the white dwarf.

Keywords
  1. Variable stars
  2. White dwarf stars
  3. Spectroscopy
  4. Ultraviolet astronomy
  5. Optical astronomy
Bibliographic source Bibcode
2019MNRAS.483.2941W
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/483/2941
IVOA Identifier IVOID
ivo://CDS.VizieR/J/MNRAS/483/2941

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History

2022-08-11T09:25:11Z
Resource record created
2022-08-11T09:25:11Z
Created
2022-08-29T10:00:06Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr