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Title: Elemental compositions of two extrasolar rocky planetesimals

We report Keck/HIRES and Hubble Space Telescope/COS spectroscopic studies of extrasolar rocky planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD 133. In G29-38, eight 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.
Authors:
; ; ;  [1] ;  [2]
  1. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562 (United States)
  2. Institut fur Theoretische Physik und Astrophysik, University of Kiel, D-24098 Kiel (Germany)
Publication Date:
OSTI Identifier:
22351608
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ELEMENT ABUNDANCE; HYDROGEN; MASS; OXYGEN; REFRACTORIES; SPACE; STEADY-STATE CONDITIONS; TELESCOPES; WHITE DWARF STARS