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Title: DETAILED COMPOSITIONAL ANALYSIS OF THE HEAVILY POLLUTED DBZ WHITE DWARF SDSS J073842.56+183509.06: A WINDOW ON PLANET FORMATION?

We present a new model atmosphere analysis of the most metal-contaminated white dwarf known, the DBZ SDSS J073842.56+183509.06. Using new high-resolution spectroscopic observations taken with Keck and Magellan, we determine precise atmospheric parameters and measure abundances of 14 elements heavier than helium. We also report new Spitzer mid-infrared photometric data that are used to better constrain the properties of the debris disk orbiting this star. Our detailed analysis, which combines data taken from seven different observational facilities (Galaxy Evolution Explorer, Gemini, Keck, Magellan, MMT, Sloan Digital Sky Survey, and Spitzer), clearly demonstrates that J0738+1835 is accreting large amounts of rocky terrestrial-like material that has been tidally disrupted into a debris disk. We estimate that the body responsible for the photospheric metal contamination was at least as large as Ceres, but was much drier, with less than 1% of the mass contained in the form of water ice, indicating that it formed interior to the snow line around its parent star. We also find a correlation between the abundances (relative to Mg and bulk Earth) and the condensation temperature; refractory species are clearly depleted, while the more volatile elements are possibly enhanced. This could be the signature of a body thatmore » formed in a lower temperature environment than where Earth formed. Alternatively, we could be witnessing the remains of a differentiated body that lost a large part of its outer layers.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Departement de Physique, Universite de Montreal, Montreal, QC H3C 3J7 (Canada)
  2. Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States)
  3. Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093-0424 (United States)
  4. Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
Publication Date:
OSTI Identifier:
22020533
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 749; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; GALACTIC EVOLUTION; GALAXIES; HELIUM; ICE; METALS; PLANETS; STELLAR ATMOSPHERES; WHITE DWARF STARS