Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal

doi:10.1126/science.abd1714

GSTDTAP > 气候变化

DOI	10.1126/science.abd1714
	Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal
	B. C. Kaiser; J. C. Clemens; S. Blouin; P. Dufour; R. J. Hegedus; J. S. Reding; A. Bédard
	2021-01-08
发表期刊	Science
出版年	2021
英文摘要	White dwarfs are dense stellar remnants left when a dying parent star throws off its outer layers. The high gravitational fields should cause heavy elements to rapidly sink below the white dwarf surface. Nevertheless some “polluted” white dwarfs have evidence for those materials on their surface, which is thought to be due to the recent accretion of rocky bodies from a surrounding planetary system. Kaiser et al. report a white dwarf with pollution by potassium and lithium. This observation provides a record of the composition of the accreted rocky bodies and of the Galactic lithium abundance when the planetary system formed, billions of years ago. Science , this issue p. [168][1] Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the systems formed, which is analogous to how meteorite abundances inform our understanding of the early Solar System. We report the detection of lithium, sodium, potassium, and calcium in the atmosphere of the white dwarf Gaia DR2 4353607450860305024, which we ascribe to the accretion of a planetesimal. Using model atmospheres, we determine abundance ratios of these elements, and, with the exception of lithium, they are consistent with meteoritic values in the Solar System. We compare the measured lithium abundance with measurements in old stars and with expectations from Big Bang nucleosynthesis. [1]: /lookup/doi/10.1126/science.abd1714
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/310447
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	B. C. Kaiser,J. C. Clemens,S. Blouin,et al. Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal[J]. Science,2021.
APA	B. C. Kaiser.,J. C. Clemens.,S. Blouin.,P. Dufour.,R. J. Hegedus.,...&A. Bédard.(2021).Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal.Science.
MLA	B. C. Kaiser,et al."Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal".Science (2021).