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Isotopic ratios for C, N, Si, Al, and Ti in C-rich presolar grains from massive stars

Schofield, Jordan; Pignatari, Marco; Stancliffe, Richard J.; Hoppe, Peter


Jordan Schofield

Marco Pignatari

Richard J. Stancliffe

Peter Hoppe


Certain types of silicon carbide (SiC) grains, e.g. SiC-X grains, and low density (LD) graphites are C-rich presolar grains that are thought to have condensed in the ejecta of core-collapse supernovae (CCSNe). In this work, we compare C, N, Al, Si, and Ti isotopic abundances measured in presolar grains with the predictions of 21 CCSN models. The impact of a range of SN explosion energies is considered, with the high energy models favouring the formation of a C/Si zone enriched in 12C, 28Si, and 44Ti. Eighteen of the 21 models have H ingested into the He-shell and different abundances of H remaining from such H-ingestion. CCSN models with intermediate to low energy (that do not develop a C/Si zone) cannot reproduce the 28Si and 44Ti isotopic abundances in grains without assuming mixing with O-rich CCSN ejecta. The most 28Si-rich grains are reproduced by energetic models when material from the C/Si zone is mixed with surrounding C-rich material, and the observed trends of the 44Ti/48Ti and 49Ti/48Ti ratios are consistent with the C-rich C/Si zone. For the models with H-ingestion, high and intermediate explosion energies allow the production of enough 26Al to reproduce the 26Al/27Al measurements of most SiC-X and LD graphites. In both cases, the highest 26Al/27Al ratio is obtained with H still present at XH ≈ 0.0024 in He-shell material when the SN shock is passing. The existence of H in the former convective He-shell points to late H-ingestion events in the last days before massive stars explode as a supernova.


Schofield, J., Pignatari, M., Stancliffe, R. J., & Hoppe, P. (2022). Isotopic ratios for C, N, Si, Al, and Ti in C-rich presolar grains from massive stars. Monthly notices of the Royal Astronomical Society, 517(2), 1803-1820.

Journal Article Type Article
Acceptance Date Aug 26, 2022
Online Publication Date Oct 13, 2022
Publication Date 2022-12
Deposit Date Apr 28, 2023
Publicly Available Date Apr 28, 2023
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 517
Issue 2
Pages 1803-1820
Public URL


Published paper (2.8 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2022 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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