Stellar origin of 15N-rich presolar SiC grains of type AB: Supernovae with explosive hydrogen burning

Liu, Nan; Nittler, Larry R.; Pignatari, Marco; Alexander, Conel M. O’D.; Wang, Jianhua

Abstract

© 2017. The American Astronomical Society. All rights reserved. We report C, N, and Si isotopic data for 59 highly 13 C-enriched presolar submicron-to micron-sized SiC grains from the Murchison meteorite, including eight putative nova grains (PNGs) and 29 15 N-rich ( 14 N/ 15 N ≤ solar) AB grains, and their Mg-Al, S, and Ca-Ti isotope data when available. These 37 grains are enriched in 13 C, 15 N, and 26 Al with the PNGs showing more extreme enhancements. The 15 N-rich AB grains show systematically higher 26 Al and 30 Si excesses than the 14 N-rich AB grains. Thus, we propose to divide the AB grains into groups 1 ( 14 N/ 15 N < solar) and 2 ( 14 N/ 15 N ≥ solar). For the first time, we have obtained both S and Ti isotopic data for five AB1 grains and one PNG and found 32 S and/or 50 Ti enhancements. Interestingly, one AB1 grain had the largest 32 S and 50 Ti excesses, strongly suggesting a neutron-capture nucleosynthetic origin of the 32 S excess and thus the initial presence of radiogenic 32 Si (t 1/2 = 153 years). More importantly, we found that the 15 N and 26 Al excesses of AB1 grains form a trend that extends to the region in the N-Al isotope plot occupied by C2 grains, strongly indicating a common stellar origin for both AB1 and C2 grains. Comparison of supernova models with the AB1 and C2 grain data indicates that these grains came from supernovae that experienced H ingestion into the He/C zones of their progenitors.

Citation

Liu, N., Nittler, L. R., Pignatari, M., Alexander, C. M. O., & Wang, J. (2017). Stellar origin of 15N-rich presolar SiC grains of type AB: Supernovae with explosive hydrogen burning. The Astrophysical journal, 842(1), L1. https://doi.org/10.3847/2041-8213/aa74e5

• Journal Article Type: Article
• Acceptance Date: May 23, 2017
• Online Publication Date: Jun 5, 2017
• Publication Date: Jun 10, 2017
• Deposit Date: Jul 7, 2017
• Publicly Available Date: Jul 7, 2017
• Journal: Astrophysical journal letters
• Print ISSN: 0004-637X
• Electronic ISSN: 2041-8213
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 842
• Issue: 1
• Pages: L1
• DOI: https://doi.org/10.3847/2041-8213/aa74e5
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://hull-repository.worktribe.com/output/453397
• Publisher URL: http://iopscience.iop.org/article/10.3847/2041-8213/aa74e5
• Additional Information: Journal title: The Astrophysical Journal; Article type: paper; Article title: Stellar Origin of 15N-rich Presolar SiC Grains of Type AB: Supernovae with Explosive Hydrogen Burning; Copyright information: © 2017. The American Astronomical Society. All rights reserved.; Date received: 2017-04-10; Date accepted: 2017-05-23; Online publication date: 2017-06-06