Pulsational Mapping Of Calcium Across The Surface Of A White Dwarf




Thompson, Susan E.
Montgomery, Michael H.
von Hippel, Ted
Nitta, Atsuko
Dalessio, J.
Provencal, J.
Strickland, W.
Holtzman, Jon A.
Mukadam, Anjum
Sullivan, D.

Journal Title

Journal ISSN

Volume Title



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.



LCSH Subject Headings


Thompson, Susan E., M. H. Montgomery, T. von Hippel, A. Nitta, J. Dalessio, J. Provencal, W. Strickland et al. "Pulsational Mapping of Calcium Across the Surface of a White Dwarf." The Astrophysical Journal, Vol. 714, No. 1 (May., 2010): 296.