The rp-Process in Neutrino-driven Winds
The rp-Process in Neutrino-driven Winds
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DOI：
10.1086/505483
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发表时间：
2006-02
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影响因子：
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通讯作者：
S. Wanajo
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文献类型：
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作者：
S. Wanajo
最近的流体动力学模拟的核心坍缩超新星与准确的中微子输运表明，大部分的早期中微子加热的喷出物是质子丰富的，其中一些有趣的质子丰富的核的生产是预期的。最近的核合成研究表明，快速质子俘获（rp）过程发生在这样的质子丰富的环境中，通过更快地俘获中子，绕过β+寿命为几分钟的等待点核，从质子吸收中微子中不断提供中子。在这项研究中，核合成计算进行了广泛的中微子光度和电子分数（叶），使用半解析模型的原中子星星风。原中子星的质量被取为1.4和2.0 M，后者被认为是对高熵风的检验（大约是2倍）。对于Ye > 0.52，中微子诱导的rp过程发生在许多风轨迹中，并且合成了有趣数量的高达A ~ 130的p核。然而，92 Mo与其他具有类似质量数的p核相比，生产有点不足。另一方面，当0.46 < Ye < 0.49时，92 Mo被源自高温α过程的丰富90 Zr附近的核流显著增强。核合成产量的平均喷出的风的质量，并进一步，在叶分布预测最近的流体动力学模拟的核心坍缩超新星。比较Ye和质量平均产额与太阳成分的关系，发现中微子驱动的风可能是A ~ 110的轻p核的起源，包括92，94 Mo和96，98 Ru，这是其他天体物理站点无法解释的。
Recent hydrodynamic simulations of core-collapse supernovae with accurate neutrino transport suggest that the bulk of the early neutrino-heated ejecta is proton rich, in which the production of some interesting proton-rich nuclei is expected. As suggested in recent nucleosynthesis studies, the rapid proton-capture (rp) process takes place in such proton-rich environments by bypassing the waiting point nuclei with β+-lives of a few minutes via the faster capture of neutrons continuously supplied from the neutrino absorption by protons. In this study, the nucleosynthesis calculations are performed with a wide range of neutrino luminosities and electron fractions (Ye), using semianalytic models of proto-neutron-star winds. The masses of proto-neutron stars are taken to be 1.4 and 2.0 M☉, where the latter is regarded as the test for somewhat high-entropy winds (about a factor of 2). For Ye > 0.52, the neutrino-induced rp-process takes place in many wind trajectories, and p-nuclei up to A ~ 130 are synthesized in interesting amounts. However, 92Mo is somewhat underproduced compared to other p-nuclei with similar mass numbers. For 0.46 < Ye < 0.49, on the other hand, 92Mo is significantly enhanced by the nuclear flows in the vicinity of the abundant 90Zr that originates from the α-process at higher temperature. The nucleosynthetic yields are averaged over the ejected masses of winds, and further, over the Ye distribution predicted by a recent hydrodynamic simulation of a core-collapse supernova. Comparison of the Ye- and mass-averaged yields to the solar compositions implies that the neutrino-driven winds can potentially be the origin of light p-nuclei up to A ~ 110, including 92,94Mo and 96,98Ru, that cannot be explained by other astrophysical sites.