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We study the role of light neutron-rich nuclei during r-process nucleosynthesis in supernovae. Most previous studies of the r-process have concentrated on the reaction flow of heavy unstable nuclei. Although the nuclear reaction network…

Astrophysics · Physics 2009-11-06 M. Terasawa , K. Sumiyoshi , T. Kajino , G. J. Mathews , I. Tanihata

We present a new nucleosynthesis process, that we denote nu p-process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the…

We investigate nucleosynthesis in the sub-relativistic outflows from black hole (BH) accretion disks formed in failed supernovae from rapidly-rotating Wolf-Rayet stars. These disks reach the neutrino-cooled regime during a portion of their…

High Energy Astrophysical Phenomena · Physics 2024-08-29 Coleman Dean , Rodrigo Fernández

An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of ~10^-3 times the solar value. Another…

Solar and Stellar Astrophysics · Physics 2015-06-03 Yong-Zhong Qian

A promising astrophysical site to produce the lighter heavy elements of the first $r$-process peak ($Z = 38-47$) is the moderately neutron rich ($0.4 < Y_e < 0.5$) neutrino-driven ejecta of explosive environments, such as core-collapse…

High Energy Astrophysical Phenomena · Physics 2022-08-17 A. Psaltis , A. Arcones , F. Montes , P. Mohr , C. J. Hansen , M. Jacobi , H. Schatz

We investigate nuclear reactions and feedback in hyperaccreting neutron star environments, considering accretion rates in the range 0.3 - $3\times10^4$ $M_\odot$ yr$^{-1}$, typical of short-period compact object binaries in common…

High Energy Astrophysical Phenomena · Physics 2025-11-25 Peter Anninos , Matthew Portman , Scott Carmichael , Robert Hoffman , Andre Sieverding

We use cosmological, magnetohydrodynamical simulations of Milky Way-mass galaxies from the Auriga project to study their enrichment with rapid neutron capture (r-process) elements. We implement a variety of enrichment models from both…

Recent studies suggest that metal-poor stars enhanced in carbon but containing low levels of neutron-capture elements may have been among the first to incorporate the nucleosynthesis products of the first generation of stars. We have…

Solar and Stellar Astrophysics · Physics 2015-06-18 Ian U. Roederer , George W. Preston , Ian B. Thompson , Stephen A. Shectman , Chris Sneden

The chemical abundances of the very metal-poor double-enhanced stars are excellent information for setting new constraints on models of neutron-capture processes at low metallicity. These stars are known as s+r stars, since they show…

Astrophysics · Physics 2009-11-11 Bo Zhang , Kun Ma , Guide Zhou

The abundance patterns of extremely metal-poor (EMP) stars provide us with important information on nucleosynthesis in supernovae (SNe) formed in a Pop III or EMP environment, and thus on the nature of the first stars in the Universe. We…

Astrophysics · Physics 2009-11-11 Ken'ichi Nomoto , Nozomu Tominaga , Hideyuki Umeda , Chiaki Kobayashi

The astrophysical production site of the heaviest elements in the universe remains a mystery. Incorporating heavy element signatures of metal-poor, $r$-process enhanced stars into theoretical studies of $r$-process production can offer…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Erika M. Holmbeck , Anna Frebel , G. C. McLaughlin , Matthew R. Mumpower , Trevor M. Sprouse , Rebecca Surman

I compare seven actively studied r-process nucleosynthesis scenarios against observed properties of r-process elements in the early Universe, and conclude that the most likely scenario to contribute to the site of elements below the third…

High Energy Astrophysical Phenomena · Physics 2026-05-12 Noam Soker

We present the nucleosynthesis of magneto-rotational supernovae (MR-SNe) including neutrino-driven and magneto-rotational-driven ejecta based, for the first time, on 2D simulations with accurate neutrino transport. The models analysed here…

High Energy Astrophysical Phenomena · Physics 2021-01-21 Moritz Reichert , Martin Obergaulinger , Marius Eichler , Miguel-Ángel Aloy , Almudena Arcones

The common envelop jet supernovae (CEJSN) r-process scenario has been proposed as an r-process nucleosynthesis site in the past decade. Jets launched by a neutron star that spirals-in inside the core of a red supergiant star in a common…

High Energy Astrophysical Phenomena · Physics 2023-10-16 Shilun Jin , Noam Soker

The cosmic origin of the elements heavier than iron has long been uncertain. Theoretical modelling shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum…

High Energy Astrophysical Phenomena · Physics 2017-10-17 Daniel Kasen , Brian Metzger , Jennifer Barnes , Eliot Quataert , Enrico Ramirez-Ruiz

Carbon-enhanced metal-poor (CEMP) stars in the Galactic Halo display enrichments in heavy elements associated with either the s (slow) or the r (rapid) neutron-capture process (e.g., barium and europium respectively), and in some cases they…

Solar and Stellar Astrophysics · Physics 2016-11-15 Melanie Hampel , Richard J. Stancliffe , Maria Lugaro , Bradley S. Meyer

We present a new set of zero metallicity models in the range 13-80 $\rm M_\odot$ together to the associated explosive nucleosynthesis. These models are fully homogeneous with the solar metallicity set we published in Limongi & Chieffi…

Solar and Stellar Astrophysics · Physics 2015-06-04 M. Limongi , A. Chieffi

We show that the low ratios of $\alpha$ elements (Mg, Si, and Ca) to Fe recently found for a small fraction of extremely metal-poor stars can be naturally explained with the nucleosynthesis yields of core-collapse supernovae, i.e.,…

Astrophysics of Galaxies · Physics 2015-06-19 Chiaki Kobayashi , Miho N. Ishigaki , Nozomu Tominaga , Ken'ichi Nomoto

In this PhD thesis we investigate stellar evolution and nucleosynthesis in the low- and extremely-low metallicity regime - including models of stars with a pure Big Bang composition (i.e. $\rm{Z} = 0$). The metallicity range of the…

Solar and Stellar Astrophysics · Physics 2024-10-30 Simon Wattana Campbell

We model the history of Galactic r-process enrichment using high-redshift, high-resolution zoom cosmological simulations of a Milky Way (MW) type halo. We assume that all r-process sources are neutron star mergers (NSMs) with a power law…

Astrophysics of Galaxies · Physics 2019-05-08 Mohammadtaher Safarzadeh , Richard Sarmento , Evan Scannapieco