SULFUR ISOTOPIC COMPOSITIONS OF SUBMICROMETER SiC GRAINS FROM THE MURCHISON METEORITE

doi:10.1088/0004-637X/799/2/156

	SULFUR ISOTOPIC COMPOSITIONS OF SUBMICROMETER SiC GRAINS FROM THE MURCHISON METEORITE
	Xu, Yuchen 1,2,3; Zinner, Ernst 2,3; Gallino, Roberto 4; Heger, Alexander 5; Pignatari, Marco 6; Lin, Yangting 7
刊名	ASTROPHYSICAL JOURNAL
	2015-02-01
卷号	799 期号:2
关键词	astrochemistry circumstellar matter nuclear reactions nucleosynthesis abundances supernovae general stars: AGB and post-AGB
ISSN号	0004-637X
DOI	10.1088/0004-637X/799/2/156
文献子类	Article
英文摘要	We report C, Si, N, S, Mg-Al, and Ca-Ti isotopic compositions of presolar silicon carbide (SiC) grains from the SiC-rich KJE size fraction (0.5-0.8 m) of the Murchison meteorite. One thousand one hundred thirteen SiC grains were identified based on their C and Si isotopic ratios. Mainstream, AB, C, X, Y, and Z subtypes of SiC, and X-type silicon nitride (Si3N4) account for 81.4%, 5.7%, 0.1%, 1.5%, 5.8%, 4.9%, and 0.4%, respectively. Twenty-five grains with unusual Si isotopic ratios, including one C grain, 16 X grains, 1 Y grain, 5 Z grains, and 2 X-type Si3N4 grains were selected for N, S, Mg-Al, and Ca-Ti isotopic analysis. The C grain is highly enriched in 29Si and 30Si (d29Si = 1345% 19%, d30Si = 1272% 19%). It has a huge 32S excess, larger than any seen before, and larger than that predicted for the Si/S supernova (SN) zone, providing evidence against the elemental fractionation model by Hoppe et al. Two SN models investigated here present a more satisfying explanation in terms of a radiogenic origin of 32S from the decay of short-lived 32Si (t 1/2 = 153 yr). Silicon-32 as well as 29Si and 30Si can be produced in SNe by short neutron bursts; evidence for initial 44Ti (t 1/2 = 60 yr) in the C grain is additional evidence for an SN origin. The X grains have marginal 32S excesses, much smaller than expected from their large 28Si excesses. Similarly, the Y and Z grains do not show the S-isotopic anomalies expected from their large Si isotopic anomalies. Low intrinsic S contents and contamination with isotopically normal S are the most likely explanations.
WOS关键词	SILICON-CARBIDE GRAINS ; CORE-COLLAPSE SUPERNOVAE ; GIANT BRANCH STARS ; PRESOLAR GRAPHITE GRAINS ; MASSIVE STARS ; SOLAR-METALLICITY ; IMPROVED NUCLEAR ; II SUPERNOVAE ; SI3N4 GRAINS ; AGB STARS
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000348820900043
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/86862]
专题	中国科学院地质与地球物理研究所
通讯作者	Xu, Yuchen
作者单位	1.Chinese Acad Sci, Inst Geochem, Guiyang 550002, Peoples R China 2.Washington Univ, Space Sci Lab, St Louis, MO 63130 USA 3.Washington Univ, Dept Phys, St Louis, MO 63130 USA 4.Univ Torino, Dipartimento Fis, I-10125 Turin, Italy 5.Monash Univ, Monash Ctr Astrophys, Sch Math Sci, Clayton, Vic 3800, Australia 6.Univ Basel, Dept Phys, CH-4056 Basel, Switzerland 7.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earths Deep Interior, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Xu, Yuchen,Zinner, Ernst,Gallino, Roberto,et al. SULFUR ISOTOPIC COMPOSITIONS OF SUBMICROMETER SiC GRAINS FROM THE MURCHISON METEORITE[J]. ASTROPHYSICAL JOURNAL,2015,799(2).
APA	Xu, Yuchen,Zinner, Ernst,Gallino, Roberto,Heger, Alexander,Pignatari, Marco,&Lin, Yangting.(2015).SULFUR ISOTOPIC COMPOSITIONS OF SUBMICROMETER SiC GRAINS FROM THE MURCHISON METEORITE.ASTROPHYSICAL JOURNAL,799(2).
MLA	Xu, Yuchen,et al."SULFUR ISOTOPIC COMPOSITIONS OF SUBMICROMETER SiC GRAINS FROM THE MURCHISON METEORITE".ASTROPHYSICAL JOURNAL 799.2(2015).