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arXiv · 1401.4252

Elemental Compositions of Two Extrasolar Rocky Planetesimals

S. Xu·M. Jura·D. Koester·B. Klein·B. Zuckerman
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Abstract

We report Keck/HIRES and HST/COS spectroscopic studies of extrasolar rocky planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD 133. In G29-38, 8 elements are detected, including C, O, Mg, Si, Ca, Ti, Cr and Fe while in GD 133, O, Si, Ca and marginally Mg are seen. These two extrasolar planetesimals show a pattern of refractory enhancement and volatile depletion. For G29-38, the observed composition can be best interpreted as a blend of a chondritic object with some refractory-rich material, a result from post-nebular processing. Water is very depleted in the parent body accreted onto G29-38, based on the derived oxygen abundance. The inferred total mass accretion rate in GD 133 is the lowest of all known dusty white dwarfs, possibly due to non-steady state accretion. We continue to find that a variety of extrasolar planetesimals all resemble to zeroth order the elemental composition of bulk Earth.

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S. Xu, M. Jura, D. Koester, B. Klein, B. Zuckerman. 2014-01-17. Elemental Compositions of Two Extrasolar Rocky Planetesimals. https://doi.org/10.1088/0004-637x/783/2/79

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