The Intermediate r-process in Core-collapse Supernovae Driven by the Magneto-rotational Instability

Nishimura, Nobuya; Sawai, Hidetomo; Takiwaki, Tomoya; Yamada, Shoichi; Thielemann, Friedrich‐Karl

doi:10.3847/2041-8213/aa5dee

Cited by 185 publications

(208 citation statements)

References 50 publications

(102 reference statements)

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“…The models of neutron star or black hole mergers, type II supernova explosions, accretiondriven gravitational collapse, etc. are proposed in the literature, and so far there is no general consensus (Nishimura et al 2017). However, all agree that the r-process must occur in stars more massive than those in which nucleosynthesis proceeds in the main component of the s-process.…”

Section: Introductionmentioning

confidence: 99%

Even-to-Odd Barium Isotope Ratio in Selected Galactic Halo Stars

Mashonkina

Belyaev

2019

Astron. Lett.

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We have updated the Ba II model atom by taking into account the H I impact excitation with the rate coefficients from the quantum-mechanical calculations of . Using high-resolution stellar spectra and the non-local thermodynamic equilibrium (non-LTE) line formation for Ba II, we have determined the fraction of barium isotopes with an odd mass number (f odd ) in four Galactic halo giants with well-known atmospheric parameters. We use a method based on the requirement that the abundances from the Ba II 4554Å resonance and Ba II 5853, 6496Å subordinate lines be equal. An accuracy of 0.04 dex in determining the barium abundance from individual lines has been achieved. In three stars (HD 2796, HD 108317, and HD 122563) f odd ≥ 0.4. This suggests that ≥ 80 % of the barium observed in these stars was synthesized in the r-process. In HD 128279 f odd = 0.27 exceeds the fraction of odd barium isotopes in the Solar system, but only slightly. The dominance of the r-process at the formation epoch of our sample stars is confirmed by the presence of a europium overabundance relative barium, with [Eu/Ba] > 0.3. We have calculated the non-LTE abundance corrections for five Ba II lines and investigated their dependence on atmospheric parameters in the ranges of effective temperatures from 4500 to 6500 K, surface gravities log g from 0.5 to 4.5, and metallicities [Fe/H] from 0 to −3.

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Section: Introductionmentioning

confidence: 99%

Even-to-Odd Barium Isotope Ratio in Selected Galactic Halo Stars

Mashonkina

Belyaev

2019

Astron. Lett.

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“…Magnetorotational (MR), or jet-driven, CCSNe (Bisnovatyi-Kogan 1970;LeBlanc & Wilson 1970;Wheeler et al 2002;Mösta et al 2014b) appear to provide far more promising conditions for r-process nucleosynthesis than neutrino-driven CCSNe (Winteler et al 2012;Nishimura et al 2015Nishimura et al , 2017, ejecting ∼ 10 −3 −10 −2 M of r-process material. While this theoretical yield is comparable to predictions for NS-NS mergers (e.g.…”

Section: Introductionmentioning

confidence: 99%

r-Process nucleosynthesis from three-dimensional jet-driven core-collapse supernovae with magnetic misalignments

Halevi

Mösta

2018

Monthly Notices of the Royal Astronomical Society

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We investigate r-process nucleosynthesis in three-dimensional general relativistic magnetohydrodynamic simulations of jet-driven supernovae resulting from rapidly rotating, strongly magnetized core-collapse. We explore the effect of misaligning the pre-collapse magnetic field with respect to the rotation axis by performing four simulations: one aligned model and models with 15°, 30°, and 45°misalignments. The simulations we present employ a microphysical finite-temperature equation of state and a leakage scheme that captures the overall energetics and lepton number exchange due to post-bounce neutrino emission and absorption. We track the thermodynamic properties of the ejected material with Lagrangian tracer particles and analyse its composition with the nuclear reaction network S N . By using different neutrino luminosities in post-processing the tracer data with S N , we constrain the impact of uncertainties in neutrino luminosities. We find that, for the aligned model considered here, the use of an approximate leakage scheme results in neutrino luminosity uncertainties corresponding to a factor of 100-1000 uncertainty in the abundance of third peak r-process elements. Our results show that for misalignments of 30°or less, r-process elements are robustly produced as long as neutrino luminosities are reasonably low ( 5 × 10 52 erg s −1 ). For a more extreme misalignment of 45°, we find the production of r-process elements beyond the second peak significantly reduced. We conclude that robust r-process nucleosynthesis in magnetorotational supernovae requires a progenitor stellar core with a large poloidal magnetic field component that is at least moderately (within ∼ 30°) aligned with the rotation axis.

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“…Support to the notion that jets play a role in the explosion of many CCSNe comes from observations (e.g., Lopez et al 2014;González-Casanova et al 2014;Milisavljevic et al 2015;Tanaka et al 2017) and theoretical arguments, including numerical simulations (e.g. Bromberg & Tchekhovskoy 2016;Gilkis 2017;Nishimura et al 2017). …”

Section: Introductionmentioning

confidence: 99%

The imprints of the last jets in core collapse supernovae

Bear

Grichener²,

Soker

2017

Monthly Notices of the Royal Astronomical Society

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We analyze the morphologies of three core collapse supernova remnants (CCSNRs) and the energy of jets in other CCSNRs and in Super Luminous Supernovae (SLSNe) of type Ib/Ic/IIb, and conclude that these properties are well explained by the last jets' episode as expected in the jet feedback explosion mechanism of core collapse supernovae (CCSNe). The presence of two opposite protrusions, termed ears, and our comparison of the CCSNR morphologies with morphologies of planetary nebulae strengthen the claim that jets play a major role in the explosion mechanism of CCSNe. We crudely estimate the energy that was required to inflate the ears in two CCSNRs, and assume that the ears were inflated by jets. We find that the energies of the jets that inflated ears in 11 CCSNRs span a range that is similar to that of jets in some energetic CCSNe (SLSNe), and that this energy, only of the last jets' episode, is much less than the explosion energy. This finding is compatible with the jet feedback explosion mechanism of CCSNe, where only the last jets, that carry a small fraction of the total energy carried by earlier jets, are expected to influence the outer parts of the ejecta. We reiterate our call for a paradigm shift from neutrino-driven to jet-driven explosion models of CCSNe.

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The Intermediate r-process in Core-collapse Supernovae Driven by the Magneto-rotational Instability

Cited by 185 publications

References 50 publications

Even-to-Odd Barium Isotope Ratio in Selected Galactic Halo Stars

Even-to-Odd Barium Isotope Ratio in Selected Galactic Halo Stars

r-Process nucleosynthesis from three-dimensional jet-driven core-collapse supernovae with magnetic misalignments

The imprints of the last jets in core collapse supernovae

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