Multiwavelength observations of the EUV variable metal-rich white dwarf GD 394
Author
Wilson, David JGänsicke, Boris T
Koester, Detlev
Toloza, Odette
Holberg, Jay B
Preval, Simon P
Barstow, Martin A
Belardi, Claudia
Burleigh, Matthew R
Casewell, Sarah L
Cauley, P Wilson
Chote, Paul
Farihi, Jay
Hollands, Mark A
Long, Knox S
Redfield, Seth
Affiliation
Univ Arizona, Lunar & Planetary LabIssue Date
2019-03
Metadata
Show full item recordPublisher
OXFORD UNIV PRESSCitation
David J Wilson, Boris T Gänsicke, Detlev Koester, Odette Toloza, Jay B Holberg, Simon P Preval, Martin A Barstow, Claudia Belardi, Matthew R Burleigh, Sarah L Casewell, P Wilson Cauley, Paul Chote, Jay Farihi, Mark A Hollands, Knox S Long, Seth Redfield, Multiwavelength observations of the EUV variable metal-rich white dwarf GD 394, Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 3, March 2019, Pages 2941–2957, https://doi.org/10.1093/mnras/sty3218Rights
© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We present new Hubble Space Telescope (HST) ultraviolet and ground-based optical observations of the hot, metal-rich white dwarf GD394. Extreme-ultraviolet (EUV) observations in 1992-1996 revealed a 1.15 d 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 GD394 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 GD394 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.ISSN
0035-8711Version
Final published versionSponsors
European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013 / ERC Grant) [320964]; Leverhulme Trust Research Project Grant; NASA [NAS 5-26555]; NASA through a Space Telescope Science Institute [13719]; W. M. Keck Foundationae974a485f413a2113503eed53cd6c53
10.1093/mnras/sty3218