Neutron star mergers versus core-collapse supernovae as dominant r-process sites in the early galaxy
Sep, 200316 pages
Published in:
- Astron.Astrophys. 416 (2004) 997-1011
e-Print:
- astro-ph/0309237 [astro-ph]
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Abstract: (arXiv)
The astrophysical nature of r-process sites is a long standing mystery and many probable sources have been suggested in the past, among them lower-mass core-collapse supernovae (in the range 8 - 10 Msol), higher-mass core-collapse supernovae (with masses > 20 Msol) and neutron star mergers. In this work, we present a detailed inhomogeneous chemical evolution study that considers for the first time neutron star mergers as major r-process sources, and compare this scenario to the ones in which core-collapse supernovae act as dominant r-process sites. We conclude that, due to the lack of reliable iron and r-process yields as function of progenitor mass, it is not possible at present to distinguish between the lower-mass and higher-mass supernovae scenarios within the framework of inhomogeneous chemical evolution. However, neutron-star mergers seem to be ruled out as the dominant r-process source, since their low rates of occurrence would lead to r-process enrichment that is not consistent with observations at very low metallicities. Additionally, the considerable injection of r-process material by a single neutron-star merger leads to a scatter in [r-process/Fe] ratios at later times which is much too large compared to observations.Note:
- 16 Pages, 6 Figures, submitted to A&A
- nuclear reactions, nucleosynthesis, abundances
- stars: abundances
- ISM: abundances
- Galaxy: abundances
- Galaxy: evolution
- Galaxy: halo
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