气候变化领域集成服务门户(CCPortal): First evidence for silica condensation within the solar protoplanetary disk

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DOI	10.1073/pnas.1722265115
	First evidence for silica condensation within the solar protoplanetary disk
	Komatsu M.; Fagan T.J.; Krot A.N.; Nagashima K.; Petaev M.I.; Kimura M.; Yamaguchi A.
发表日期	2018
ISSN	0027-8424
起始页码	7497
结束页码	7502
卷号	115 期号:29
英文摘要	Calcium-aluminum–rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs), a refractory component of chondritic meteorites, formed in a high-temperature region of the protoplanetary disk characterized by approximately solar chemical and oxygen isotopic (Δ17O ∼ −24) compositions, most likely near the protosun. Here we describe a16O-rich (Δ17O ∼ −22 ± 2) AOA from the carbonaceous Renazzo-type (CR) chondrite Yamato-793261 containing both (i) an ultrarefractory CAI and (II) forsterite, low-Ca pyroxene, and silica, indicating formation by gas–solid reactions over a wide temperature range from -1,800 to -1,150 K. This AOA provides direct evidence for gas–solid condensation of silica in a CAI/AOA-forming region. In a gas of solar composition, the Mg/Si ratio exceeds 1, and, therefore, silica is not predicted to condense under equilibrium conditions, suggesting that the AOA formed in a parcel of gas with fractionated Mg/Si ratio, most likely due to condensation of forsterite grains. Thermodynamic modeling suggests that silica formed by condensation of nebular gas depleted by -10× in H and He that cooled at 50 K/hour at total pressure of 10−4 bar. Condensation of silica from a hot, chemically fractionated gas could explain the origin of silica identified from infrared spectroscopy of remote protostellar disks. © 2018 National Academy of Sciences. All rights reserved.
英文关键词	Meteorites; Protoplanetary disk; Refractory inclusions
语种	英语
scopus关键词	aluminosilicate calcium; magnesium; silicon; silicon dioxide; Article; astronomy; fractionation; infrared spectroscopy; polymerization; prediction; priority journal; protoplanetary disk; temperature measurement; thermodynamics
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160492
作者单位	Komatsu, M., Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0193, Japan, Department of Earth Sciences, Waseda University, Shinjuku, Tokyo 169-8050, Japan; Fagan, T.J., Department of Earth Sciences, Waseda University, Shinjuku, Tokyo 169-8050, Japan; Krot, A.N., Hawai‘i Institute of Geophysics and Planetology, School of Ocean, Earth Science and Technology, University of Hawai‘i at Manoa, Honolulu, HI 96822, United States; Nagashima, K., Hawai‘i Institute of Geophysics and Planetology, School of Ocean, Earth Science and Technology, University of Hawai‘i at Manoa, Honolulu, HI 96822, United States; Petaev, M.I., Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, United States, Harvard–Smithsonian Center for Astrophysics, Cambridge, MA 02138, United States; Kimura, M., National Institute of Polar Research, Tachikawa, Tokyo, 190-8518, Japan, Ibaraki University, Mito, 310-8512, Japan; Yamaguchi, A., National Institute of Polar Research, Tachika...
推荐引用方式 GB/T 7714	Komatsu M.,Fagan T.J.,Krot A.N.,et al. First evidence for silica condensation within the solar protoplanetary disk[J],2018,115(29).
APA	Komatsu M..,Fagan T.J..,Krot A.N..,Nagashima K..,Petaev M.I..,...&Yamaguchi A..(2018).First evidence for silica condensation within the solar protoplanetary disk.Proceedings of the National Academy of Sciences of the United States of America,115(29).
MLA	Komatsu M.,et al."First evidence for silica condensation within the solar protoplanetary disk".Proceedings of the National Academy of Sciences of the United States of America 115.29(2018).