Six White Dwarfs with Circumstellar Silicates
arXiv:0811.1740 · doi:10.1088/0004-6256/137/2/3191
Abstract
Spitzer Space Telescope spectra reveal 10 micron silicate emission from circumstellar dust orbiting six externally-polluted white dwarfs. Micron-size glasses with an olivine stoichiometry can account for the distinctively broad wings that extend to 12 microns; these particles likely are produced by tidal-disruption of asteroids. The absence of infrared PAH features is consistent with a scenario where extrasolar rocky planets are assembled from carbon-poor solids.
21 pages, 7 figures, AJ, in press