外中子星壳减压与r过程核合成
The decompression of the outer neutron star crust and r-process nucleosynthesis
摘要：
快速中子俘获过程，或称r过程，是解释自然界中观察到的大约一半A>60稳定核的起源的基础。近年来，核天体物理学家发展了越来越复杂的r过程模型，通过加入新的天体物理或核物理成分，以令人满意的方式解释太阳系的组成。尽管有这些努力，r过程的天体物理学位置仍然不明。中子星外壳物质的组成进行了研究后，减压后，其可能的喷射。估算了减压前后中子星外壳的组成。两种不同的可能的初始条件被认为是，即一个理想化的地壳组成的冷催化物质和地壳最初在核统计平衡在10 GK左右的温度。我们表明，在这第二种情况下，减压前，在温度通常对应于8 GK，库仑效应，由于在地壳中的高密度导致的整体组成的外地壳中的中子丰富的核与质量分布接近太阳系的r-丰度分布。然而，这种分布与太阳分布不同，这是由于第二个峰值向较低值的系统性偏移。减压后，在热的外层地壳中每个种子核捕获的少量中子导致稳定的富中子核的最终分布，其质量分布为80 < A < 140个核，与太阳分布非常一致，前提是外层地壳最初的温度约为8 GK，并且外层地壳的所有层都被抛出。中子星物质从外壳的减压为轻物质的鲁棒r处理提供了合适的条件，即，r-核，A < 140。
英文摘要：
The rapid neutron-capture process, or r-process, is known to be fundamental for explaining the origin of approximately half of the A>60 stable nuclei observed in nature. In recent years nuclear astrophysicists have developed more and more sophisticated r-process models, by adding new astrophysical or nuclear physics ingredients to explain the solar system composition in a satisfactory way. Despite these efforts, the astrophysical site of the r-process remains unidentified. The composition of the neutron star outer crust material is investigated after the decompression that follows its possible ejection. The composition of the outer crust of a neutron star is estimated before and after decompression. Two different possible initial conditions are considered, namely an idealized crust composed of cold catalyzed matter and a crust initially in nuclear statistical equilibrium at temperatures around 10 GK. We show that in this second case before decompression and at temperatures typically corresponding to 8 GK, the Coulomb effect due to the high densities in the crust leads to an overall composition of the outer crust in neutron-rich nuclei with a mass distribution close to the solar system r-abundance distribution. Such distributions differ, however, from the solar one due to a systematic shift in the second peak to lower values. After decompression, the capture of the few neutrons per seed nucleus available in the hot outer crust leads to a final distribution of stable neutron-rich nuclei with a mass distribution of 80 < A < 140 nuclei in excellent agreement with the solar distribution, provided the outer crust is initially at temperatures around 8 GK and all layers of the outer crust are ejected. The decompression of the neutron star matter from the outer crust provides suitable conditions for a robust r-processing of the light species, i.e., r-nuclei with A < 140.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
