The Experts below are selected from a list of 681 Experts worldwide ranked by ideXlab platform
M Jura - One of the best experts on this subject based on the ideXlab platform.
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a pilot search for evidence of Extrasolar earth analog plate tectonics
The Astrophysical Journal, 2014Co-Authors: M Jura, B Klein, Edward D YoungAbstract:Relative to calcium, both strontium and barium are markedly enriched in Earth's continental crust compared to the basaltic crusts of other differentiated Rocky bodies within the solar system. Here, we both re-examine available archived Keck spectra to place upper bounds on n(Ba)/n(Ca) and revisit published results for n(Sr)/n(Ca) in two white dwarfs that have accreted Rocky planetesimals. We find that at most only a small fraction of the pollution is from crustal material that has experienced the distinctive elemental enhancements induced by Earth-analog plate tectonics. In view of the intense theoretical interest in the physical structure of Extrasolar Rocky Planets, this search should be extended to additional targets.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
The Astrophysical Journal, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. The best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. Best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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six white dwarfs with circumstellar silicates
arXiv: Astrophysics, 2008Co-Authors: M Jura, J Farihi, B ZuckermanAbstract: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.
B Klein - One of the best experts on this subject based on the ideXlab platform.
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a pilot search for evidence of Extrasolar earth analog plate tectonics
The Astrophysical Journal, 2014Co-Authors: M Jura, B Klein, Edward D YoungAbstract:Relative to calcium, both strontium and barium are markedly enriched in Earth's continental crust compared to the basaltic crusts of other differentiated Rocky bodies within the solar system. Here, we both re-examine available archived Keck spectra to place upper bounds on n(Ba)/n(Ca) and revisit published results for n(Sr)/n(Ca) in two white dwarfs that have accreted Rocky planetesimals. We find that at most only a small fraction of the pollution is from crustal material that has experienced the distinctive elemental enhancements induced by Earth-analog plate tectonics. In view of the intense theoretical interest in the physical structure of Extrasolar Rocky Planets, this search should be extended to additional targets.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
The Astrophysical Journal, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. The best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. Best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
B Zuckerman - One of the best experts on this subject based on the ideXlab platform.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
The Astrophysical Journal, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. The best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. Best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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six white dwarfs with circumstellar silicates
arXiv: Astrophysics, 2008Co-Authors: M Jura, J Farihi, B ZuckermanAbstract: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.
P Dufour - One of the best experts on this subject based on the ideXlab platform.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
The Astrophysical Journal, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. The best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. Best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
Carl Melis - One of the best experts on this subject based on the ideXlab platform.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
The Astrophysical Journal, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. The best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
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an aluminum calcium rich iron poor white dwarf star evidence for an Extrasolar planetary lithosphere
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B Zuckerman, B Klein, D Koester, P Dufour, Carl Melis, M JuraAbstract:The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of Rocky objects that currently or previously orbited these stars. We have measured the abundances of various elements in the hydrogen-atmosphere white dwarfs G149-28 and NLTT 43806. In comparison with other white dwarfs with atmospheres polluted by heavy elements, NLTT 43806 is substantially enriched in aluminum but relatively poor in iron. We compare the relative abundances of Al and eight other heavy elements seen in NLTT 43806 with the elemental composition of bulk Earth, with simulated Extrasolar Rocky Planets, with solar system meteorites, with the atmospheric compositions of other polluted white dwarfs, and with the outer layers of the Moon and Earth. Best agreement is found with a model that involves accretion of a mixture of terrestrial crust and upper mantle material onto NLTT 43806. The implication is that NLTT 43806 is orbited by a differentiated Rocky planet, perhaps quite similar to Earth, that has suffered a collision that stripped away some of its outer layers.
