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

Abstract

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.

Citation

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. https://doi.org/10.1093/mnras/stac2498

• 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
• DOI: https://doi.org/10.1093/mnras/stac2498
• Public URL: https://hull-repository.worktribe.com/output/4176287