University of Hull logo

Carbon-rich presolar grains from massive stars : subsolar ¹²C/¹³C and ¹⁴N/¹⁵N ratios and the mystery of ¹⁵N

Pignatari, M.; Zinner, E.; Hoppe, P.; Jordan, C. J.; Gibson, B. K.; Trappitsch, R.; Herwig, F.; Fryer, C.; Hirschi, R.; Timmes, F. X.

Authors

E. Zinner

P. Hoppe

C. J. Jordan

R. Trappitsch

F. Herwig

C. Fryer

R. Hirschi

F. X. Timmes

Abstract

Carbon-rich grains with isotopic anomalies compared to the Sun are found in primitive meteorites. They were made by stars, and carry the original stellar nucleosynthesis signature. Silicon carbide grains of Type X and C and low-density (LD) graphites condensed in the ejecta of core-collapse supernovae. We present a new set of models for the explosive He shell and compare them with the grains showing ¹²C/¹³C and ¹⁴N/¹⁵N ratios lower than solar. In the stellar progenitor H was ingested into the He shell and not fully destroyed before the explosion. Different explosion energies and H concentrations are considered. If the supernova shock hits the He-shell region with some H still present, the models can reproduce the C and N isotopic signatures in C-rich grains. Hot-CNO cycle isotopic signatures are obtained, including a large production of ¹³C and ¹⁵N. The short-lived radionuclides ²²Na and ²⁶Al are increased by orders of magnitude. The production of radiogenic ²²Ne from the decay of ²²Na in the He shell might solve the puzzle of the Ne-E(L) component in LD graphite grains. This scenario is attractive for the SiC grains of type AB with ¹⁴N/¹⁵N ratios lower than solar, and provides an alternative solution for SiC grains originally classified as nova grains. Finally, this process may contribute to the production of ¹⁴N and ¹⁵N in the Galaxy, helping to produce the ¹⁴N/¹⁵N ratio in the solar system.

Journal Article Type Article
Publication Date Aug 1, 2015
Journal Astrophysical journal letters
Print ISSN 2041-8205
Electronic ISSN 2041-8213
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 808
Issue 2
Article Number ARTN L43
Pages L43
Institution Citation Pignatari, M., Zinner, E., Hoppe, P., Jordan, C. J., Gibson, B. K., Trappitsch, R., …Timmes, F. X. (2015). Carbon-rich presolar grains from massive stars : subsolar ¹²C/¹³C and ¹⁴N/¹⁵N ratios and the mystery of ¹⁵N. Astrophysical journal. Letters, 808(2), L43. https://doi.org/10.1088/2041-8205/808/2/l43
DOI https://doi.org/10.1088/2041-8205/808/2/l43
Keywords Nuclear reactions, Nucleosynthesis, Abundances, Stars: abundances, Stars: evolution, Stars: interiors, Supernovae: general
Publisher URL http://iopscience.iop.org/article/10.1088/2041-8205/808/2/L43/meta;jsessionid=B11A6023A3F5F555838AEFABF647069B.c1.iopscience.cld.iop.org
Copyright Statement © 2015. The American Astronomical Society. All rights reserved.
Additional Information Copy of article published in: Astrophysical journal letters, 2015, v.808, issue 2

Files

document.pdf (1.1 Mb)
PDF

Copyright Statement
© 2015. The American Astronomical Society. All rights reserved.



You might also like


Downloadable Citations