Evolution of Massive Stars Up to the End of Central Oxygen Burning

Eid, M. F. El; Meyer, B. S.; The, Lih‐Sin

doi:10.1086/422162

Cited by 62 publications

(86 citation statements)

References 32 publications

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“…On average, comparing the core masses at the ignition of each fuel we find our models to be 0.5 M heavier than those of El Eid et al (2004). This can be explained as they use the Schwarzschild criterion everywhere and only study using Ledoux for convective boundaries in a 25 M model.…”

Section: Summary and Discussionmentioning

confidence: 81%

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On Variations of Pre-Supernova Model Properties

Farmer¹,

Fields²,

Petermann³

et al. 2016

ApJS

138

166

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We explore the variation in single star 15-30 M , non-rotating, solar metallicity, pre-supernova MESA models due to changes in the number of isotopes in a fully-coupled nuclear reaction network and adjustments in the mass resolution. Within this two-dimensional plane we quantitatively detail the range of core masses at various stages of evolution, mass locations of the main nuclear burning shells, electron fraction profiles, mass fraction profiles, burning lifetimes, stellar lifetimes, and compactness parameter at core-collapse for models with and without mass loss. Up to carbon burning we generally find mass resolution has a larger impact on the variations than the number of isotopes, while the number of isotopes plays a more significant role in determining the span of the variations for neon, oxygen and silicon burning. Choice of mass resolution dominates the variations in the structure of the intermediate convection zone and secondary convection zone during core and shell hydrogen burning respectively, where we find a minimum mass resolution of ≈0.01 M is necessary to achieve convergence in the helium core mass at the ≈5% level. On the other hand, at the onset of core-collapse we find ≈30% variations in the central electron fraction and mass locations of the main nuclear burning shells, a minimum of ≈127 isotopes is needed to attain convergence of these values at the ≈10% level.

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Section: Summary and Discussionmentioning

confidence: 81%

“…Stellar models with and without mass loss have similar ages, with a trend for stars with mass loss to have shorter lifetimes (e.g., El Eid et al 2004). The spread in age is larger for models without mass loss than those with mass loss.…”

Section: Stellar Lifetimesmentioning

confidence: 99%

On Variations of Pre-Supernova Model Properties

Farmer¹,

Fields²,

Petermann³

et al. 2016

ApJS

138

166

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“…The neutronization, entropy profile, and 12 C/ 16 O ratio that emerges from core helium-burning influences the subsequent evolution of a massive star. The uncertainty of the 12 C(α, γ) 16 O rate propagates to the subsequent carbon, neon, oxygen, and silicon burning stages (e.g., El Eid et al, 2004;Imbriani et al, 2001). For example, upon helium depletion the core again contracts and heats to conditions conducive to carbon burning by the 12 C + 12 C reaction.…”

Section: B Helium Burning In Massive Starsmentioning

confidence: 99%

The C12(α,γ)O16
deBoer
¹
,
Görres
²
,
Wiescher
³

et al. 2017
Rev. Mod. Phys.
208
8
143
1
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The creation of carbon and oxygen in our universe is one of the forefront questions in nuclear astrophysics. The determination of the abundance of these elements is key to both our understanding of the formation of life on earth and to the life cycles of stars. While nearly all models of different nucleosynthesis environments are affected by the production of carbon and oxygen, a key ingredient, the precise determination of the reaction rate of 12 C(α, γ) 16 O, has long remained elusive. This is owed to the reaction's inaccessibility, both experimentally and theoretically. Nuclear theory has struggled to calculate this reaction rate because the cross section is produced through different underlying nuclear mechanisms. Isospin selection rules suppress the E1 component of the ground state cross section, creating a unique situation where the E1 and E2 contributions are of nearly equal amplitudes. Experimentally there have also been great challenges. Measurements have been pushed to the limits of state of the art techniques, often developed for just these measurements. The data have been plagued by uncharacterized uncertainties, often the result of the novel measurement techniques, that have made the different results challenging to reconcile. However, the situation has markedly improved in recent years, and the desired level of uncertainty, ≈10%, may be in sight. In this review the current understanding of this critical reaction is summarized. The emphasis is placed primarily on the experimental work and interpretation of the reaction data, but discussions of the theory and astrophysics are also pursued. The main goal is to summarize and clarify the current understanding of the reaction and then point the way forward to an improved determination of the reaction rate.

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“…The 12 C(α, γ) 16 O reaction plays a major role in nuclear astrophysics [47], as it determines the 12 C/ 16 O ratio after helium burning. In the nuclear physics point of view, the 12 C(α, γ) 16 O cross section is very difficult for several reasons.…”

Section: Specific Examples 41 R-matrix Parameterizations Of the 12 Cmentioning

confidence: 99%