Pulsational Mapping of Calcium Across the Surface of a White Dwarf
arXiv:1003.3374 · doi:10.1088/0004-637X/714/1/296
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.
Accepted to the Astrophysical Journal. 16 pages, 10 figures.
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- The WIRED Survey. IV. New Dust Disks from the McCook & Sion White Dwarf Catalog
- Infrared Variability of Two Dusty White Dwarfs
- Importance of fingering convection for accreting white dwarfs in the framework of full evolutionary calculations: the case of the hydrogen-rich white dwarfs GD133 and G29-38
- Polarization measurements of the polluted white dwarf G29-38
- Skynet Algorithm for Single-Dish Radio Mapping I: Contaminant-Cleaning, Mapping, and Photometering Small-Scale Structures
- White Dwarf Variability with gPhoton: Pulsators
- White dwarf magnetospheres: Shielding volatile content of icy objects and implications for volatile pollution scarcity