Extrasolar Refractory-Dominated Planetesimals: an Assessment

Abstract

Previously published observations of 60 externally-polluted white dwarfs show that none of the stars have accreted from intact refractory-dominated parent bodies composed mainly of Al, Ca and O, although planetesimals with such a distinctive composition have been predicted to form. We propose that such remarkable objects are not detected, by themselves, because, unless they are scattered outward from their initial orbit, they are engulfed and destroyed during the star's Asymptotic Giant Branch evolution. As-yet, there is at most only weak evidence supporting a scenario where the composition of any extrasolar minor planet can be explained by blending of an outwardly scattered refractory-dominated planetesimal with an ambient asteroid.

Accepted for publication in the Astronomical Journal, 20 pages, 3 figures, 1 table

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Cited by in corpus (11)

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• 26Al in the Early Solar System: Not so Unusual After All
• Does a Differentiated, Carbonate-Rich, Rocky Object Pollute the White Dwarf SDSSJ104341.53+085558.2?
• Another one grinds the dust: Variability of the planetary debris disc at the white dwarf SDSS J104341.53+085558.2
• The Hyades Cluster: Identification of a Planetary System and Escaping White Dwarfs
• Extreme abundance ratios in the polluted atmosphere of the cool white dwarf NLTT19868
• A subtle IR excess associated with a young White Dwarf in the Edinburgh-Cape Blue Object Survey
• The polluted atmosphere of the white dwarf NLTT 25792 and the diversity of circumstellar environments