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Using failed supernovae to constrain the Galactic r-process element production

Wehmeyer, B; Wehmeyer, B.; Fröhlich, C; Fröhlich, C.; Côté, B; Côté, B.; Pignatari, M; Pignatari, M.; Thielemann, F-K; Thielemann, F. K.

Authors

B Wehmeyer

B. Wehmeyer

C Fröhlich

C. Fröhlich

B Côté

B. Côté

F-K Thielemann

F. K. Thielemann



Abstract

Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a factor of 3 in younger Galactic disc stars. The large scatter of r-process elements in the early Galaxy suggests that the r-process is made by rare events, like compact binary mergers and rare sub-classes of supernovae. Although being rare, neutron star mergers alone have difficulties to explain the observed enhancement of r-process elements in the lowest metallicity stars compared to Fe. The supernovae producing the two neutron stars already provide a substantial Fe abundance where the r-process ejecta from the merger would be injected. In this work we investigate another complementary scenario, where the r-process occurs in neutron star-black hole mergers in addition to neutron star mergers. Neutron star-black hole mergers would eject similar amounts of r-process matter as neutron star mergers, but only the neutron star progenitor would have produced Fe. Furthermore, a reduced efficiency of Fe production from single stars significantly alters the age–metallicity relation, which shifts the onset of r-process production to lower metallicities. We use the high-resolution [(20 pc)3/cell] inhomogeneous chemical evolution tool ‘ICE’ to study the outcomes of these effects. In our simulations, an adequate combination of neutron star mergers and neutron star-black hole mergers qualitatively reproduces the observed r-process abundances in the Galaxy.

Journal Article Type Article
Publication Date Aug 1, 2019
Journal Monthly notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press (OUP)
Peer Reviewed Peer Reviewed
Volume 487
Issue 2
Pages 1745-1753
APA6 Citation Wehmeyer, B., Wehmeyer, B., Fröhlich, C., Fröhlich, C., Côté, B., Côté, B., …Thielemann, F. K. (2019). Using failed supernovae to constrain the Galactic r-process element production. Monthly notices, containing papers, abstracts of papers, and reports of the proceedings of the Society, 487(2), 1745-1753. https://doi.org/10.1093/mnras/stz1310
DOI https://doi.org/10.1093/mnras/stz1310
Keywords Space and Planetary Science; Astronomy and Astrophysics
Publisher URL https://academic.oup.com/mnras/article/487/2/1745/5490380

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Copyright Statement
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model







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