Photodisintegration-triggered Nuclear Energy Release in Superbursts
Photodisintegration-triggered Nuclear Energy Release in Superbursts
复制标题
超级爆发中光崩解引发的核能释放
DOI：
10.1086/368107
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
A. Cumming
中科院分区：
文献类型：
--
作者：
H. Schatz;L. Bildsten;A. Cumming
来自吸积中子星的超暴提供了一个独特的机会来探测密度为109g cm-3、温度为T&gT；109K的核过程。卡明和比尔德斯滕发现，这些1042Erg爆发很可能是由先前氢和氦的快速燃烧过程中产生的重核中少量碳的不稳定点火所引发的。我们在这里表明，在超暴期间达到的高温会导致光解反应，从而触发这些重原子核转化为铁族元素。重核的丰度允许(γ，n)反应引发光崩解失控。由于重元素最初的结合能远不是最小的，在这个过程中释放的核能很容易超过碳的聚变释放的能量。据我们所知，这是唯一一种宇宙现象，其中重原子核被破坏成更轻的原子核是主要的能量来源。
Superbursts from accreting neutron stars present a unique opportunity to probe nuclear processes at densities ρ ≈ 109 g cm-3 and temperatures T > 109 K. Cumming & Bildsten showed that these 1042 erg bursts are most likely triggered by unstable ignition of a small amount of carbon in a sea of heavy nuclei made during prior rp-process burning of hydrogen and helium. We show here that the high temperatures reached during superbursts lead to photodisintegration reactions, which trigger conversion of these heavy nuclei into iron group elements. The neutron richness of the heavy nuclei allow (γ, n) reactions to trigger the photodisintegration runaway. Because the heavy elements are initially far from the minimum in binding energy, the nuclear energy release in this process can easily dominate that from the fusion of carbon. To our knowledge, this is the only cosmic phenomenon where the destruction of heavy nuclei into lighter nuclei represents the main source of energy.