A new site for the astrophysical gamma-process

Howard, W. M.; Meyer, B. S.; Woosley, S. E.

doi:10.1086/186038

Cited by 144 publications

(122 citation statements)

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“…A recent extension of the Woosley-Howard work by Howard et al (1991) has identified a plausible site for the ␥ process. They find the requisite thermodynamic and seed conditions to occur when a carbon-oxygen white dwarf explodes, either as Type Ia or a subclass of a Type II supernova.…”

Section: The ␥ Processmentioning

confidence: 98%

Synthesis of the elements in stars: forty years of progress

et al. 1997

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Forty years ago Burbidge, Burbidge, Fowler, and Hoyle combined what we would now call fragmentary evidence from nuclear physics, stellar evolution and the abundances of elements and isotopes in the solar system as well as a few stars into a synthesis of remarkable ingenuity. Their review provided a foundation for forty years of research in all of the aspects of low energy nuclear experiments and theory, stellar modeling over a wide range of mass and composition, and abundance studies of many hundreds of stars, many of which have shown distinct evidence of the processes suggested by B 2 FH. In this review we summarize progress in each of these fields with emphasis on the most recent developments. [S0034-6861(97)

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Section: The ␥ Processmentioning

confidence: 98%

Synthesis of the elements in stars: forty years of progress

et al. 1997

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“…In contrast, recent model calculations indicate that the p-process yield of 152 Gd is much smaller, probably not exceeding 12 % [7,8]. On the other hand, there is a non-negligible 152 Gd contribution from the s-process in massive stars, which amounts to rv6 % for a weighted average over a generation of massive stars [9].…”

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confidence: 87%

“…An empirical estimate based on the abundances of nearby p- only isotopes suggests a large correction for 152 Gd of up to 50% [6). However, improved calculations [7,8,43) have reported p-process yields of less than 12% for this isotope. Another contribution to the 152 Gd abundance comes from the s-process in massive stars, which is estimated to account for about 6% of the solar value [9).…”

Section: Input Datamentioning

confidence: 99%

Stellar neutron capture cross sections of the Gd isotopes

Wisshak¹,

Voß²,

Käppeler³

et al. 1995

Phys. Rev. C

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The neutron capture cross sections of 152 Gd, 154 Gd, 155 Gd, 156 Gd, 157 Gd, and 158 Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7 Li(p,n)1Be reaction by bombarding metallic Li targets with a pulsed protori beam. Capture events were registered with the Karlsruhe 47r Barium Fluoride Detector, which was improved by replacing crystals with high a background and by introducing a pierced crystal at zero degrees with respect to the beam axis. These changes resulted in a significantly increased efficiency for capture events. The main experimental problern was that the samples of the two s-only isotopes 152 Gd and 154 Gd showed only relatively low enrichment, but the spectroscopic quality of the BaF 2 detector allowed to determine the resulting corrections for isotopic impurities reliably. The cross section ratios could be determined with an overall uncertainty of typically 1%, an improvement by factors of five to ten compared to existing data. Severe discrepancies were found with respect to previous results. Maxwellian averaged neutron capture cross sections were calculated forthermal energies between kT = 10 keV and 100 keV. The new stellar cross sections were used for an updated analysis of the s-process reaction flow in the mass region between samarium and gadolinium, which is characterized by branchings at 151 Sm, 154 Eu, and 155 Eu. With the classical approach, the s-process temperature could be constrained corresponding to a range of thermal energies between kT=28 ke V and 33 keV. The 152 Gd production in low mass starswas found to depend strongly on the neutron freeze-out at the end of the heliumshell burning episodes.

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“…Alternative sites include type Ia supernovae [16,17] but, although the nuclear seed distribution is different, the photodisintegration mechanism remains similar. Although the γ-process does not involve reaction equilibria, again nuclear structure determines the reaction flow and similar reasoning as for the νp-process can be applied.…”

Section: The γ-Processmentioning

confidence: 99%

Proton-rich nucleosynthesis and nuclear physics

Rauscher

Fröhlich

2012

AIP Conference Proceedings

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Abstract. Although the detailed conditions for explosive nucleosynthesis are derived from astrophysical modeling, nuclear physics determines fundamental patterns in abundance yields, not only for equilibrium processes. Focussing on the νp-and the γ-process, general nucleosynthesis features within the range of astrophysical models, but (mostly) independent of details in the modelling, are presented. Remaining uncertainties due to uncertain Q-values and reaction rates are discussed.

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A new site for the astrophysical gamma-process

Cited by 144 publications

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Synthesis of the elements in stars: forty years of progress

Synthesis of the elements in stars: forty years of progress

Stellar neutron capture cross sections of the Gd isotopes

Proton-rich nucleosynthesis and nuclear physics

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