NuGrid: S process in massive stars

R. Hirschi, U. Frischknecht, M. Pignatari, F. K. Thielemann, M. E. Bennett, S. Diehl, C. L. Fryer, F. Herwig, A. Hungerford, G. Magkotsios, G. Rockefeller, Francis Timmes, Patrick Young

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The s-process production in massive stars at very low metallicities is expected to be negligible due to the low abundance of the neutron source 22Ne, to primary neutron poisons and decreasing iron seed abundances. However, recent models of massive stars including the effects of rotation show that a strong production of 22Ne is possible in the helium core, as a consequence of the primary nitrogen production (observed in halo metal poor stars). Using the PPN post-processing code (developed within the NuGrid collaboration), we study the impact of this primary 22Ne on the s process. We find a large production of s elements between strontium and barium, starting with the amount of primary 22Ne predicted by stellar models including the effects of rotation. There are several key reaction rate uncertainties influencing the s-process efficiency. For example, within the nuclear reaction rate uncertainty, the 17O(α, γ) reaction may either be critically important or negligible. We also report on the development of the new parallel (MPI) post-processing (MPPNP) variant of the PPN code designed to follow the complete nucleosynthesis in stars on highly resolved grids. We present here the first post-processing run from the ZAMS up to the end of helium burning for a 15 M model.

Original languageEnglish (US)
Title of host publicationProceedings of Science
StatePublished - 2008
Event10th Symposium on Nuclei in the Cosmos, NIC 2008 - Mackinac Island, MI, United States
Duration: Jul 27 2008Aug 1 2008


Other10th Symposium on Nuclei in the Cosmos, NIC 2008
Country/TerritoryUnited States
CityMackinac Island, MI

ASJC Scopus subject areas

  • General


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