Pulsational Mapping of Calcium Across the Surface of a White Dwarf

Susan E. Thompson, Ted von Hippel, et al.

Research output: Contribution to journalArticlepeer-review

Abstract

We constrain the distribution of calcium across the surface of the white dwarf star G29-38 by combining time-series spectroscopy from Gemini-North with global time-series photometry from the Whole Earth Telescope. G29-38 is actively accreting metals from a known debris disk. Since the metals sink significantly faster than they mix across the surface, any inhomogeneity in the accretion process will appear as an inhomogeneity of the metals on the surface of the star. We measure the flux amplitudes and the calcium equivalent width amplitudes for two large pulsations excited on G29-38 in 2008. The ratio of these amplitudes best fits a model for polar accretion of calcium and rules out equatorial accretion.

Original languageAmerican English
JournalThe Astrophysical Journal
Volume714
DOIs
StatePublished - May 1 2010
Externally publishedYes

Keywords

  • accretion
  • accretion disks
  • stars: individual (G29-38)
  • stars: oscillations
  • white dwarfs

Disciplines

  • Stars, Interstellar Medium and the Galaxy

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