CARBON SYNTHESIS IN STEADY-STATE HYDROGEN AND HELIUM BURNING ON ACCRETING NEUTRON STARS
CARBON SYNTHESIS IN STEADY-STATE HYDROGEN AND HELIUM BURNING ON ACCRETING NEUTRON STARS
复制标题
吸积中子星上稳态氢和氦燃烧的碳合成
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
H. Schatz
中科院分区：
文献类型：
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作者：
J. Stevens;E. Brown;A. Cumming;R. Cyburt;H. Schatz
吸积中子星产生的超暴探测极高密度(ρ≈109 g cm−3)和极高温度(T&gT；109 K)下的核反应。这些爆发(∼的能量是I型X射线爆发的1,000倍)最有可能是由在常规I型X射线爆发(积累的氢和氦被燃烧)的快速质子捕获过程(RP过程)期间，重核海洋中碳的不稳定点火引发的。一个悬而未决的问题是，足够数量的碳的来源是什么，在X射线爆发的RP过程中，碳在很大程度上被破坏了。我们探索了通过RP过程在稳态燃烧中产生碳，这可能与显示超爆发的系统中的不稳定燃烧一起发生。我们发现，对于大范围的吸积率和吸积的氦质量分数，会产生大量的碳，即使是对于吸收了太阳成分的系统也是如此。这使得稳定的氢和氦燃烧成为引发超级爆发的可行的碳来源。我们还考察了结果对核反应的敏感性。我们发现，~(14)O(α，p)~(17)F的反应速率在~(12)C产额中引入了最大的不确定性。
Superbursts from accreting neutron stars probe nuclear reactions at extreme densities (ρ ≈ 109 g cm−3) and temperatures (T > 109 K). These bursts (∼1000 times more energetic than type I X-ray bursts) are most likely triggered by unstable ignition of carbon in a sea of heavy nuclei made during the rapid proton capture process (rp-process) of regular type I X-ray bursts (where the accumulated hydrogen and helium are burned). An open question is the origin of sufficient amounts of carbon, which is largely destroyed during the rp-process in X-ray bursts. We explore carbon production in steady-state burning via the rp-process, which might occur together with unstable burning in systems showing superbursts. We find that for a wide range of accretion rates and accreted helium mass fractions large amounts of carbon are produced, even for systems that accrete solar composition. This makes stable hydrogen and helium burning a viable source of carbon to trigger superbursts. We also investigate the sensitivity of the results to nuclear reactions. We find that the 14O(α, p)17F reaction rate introduces by far the largest uncertainties in the 12C yield.