Dynamical ejecta of neutron star mergers with nucleonic weak processes I: Nucleosynthesis
Dynamical ejecta of neutron star mergers with nucleonic weak processes I: Nucleosynthesis
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中子星合并与核子弱过程的动力学喷射物Ⅰ：核合成
DOI：
10.1093/mnras/stab3393
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
H. Janka
中科院分区：
文献类型：
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作者：
I. Kullmann;S. Goriely;O. Just;R. Ardevol;A. Bauswein;H. Janka
我们提出了一个一致的研究中微子相互作用的影响r-过程元素核合成和加热率所产生的放射性元素合成的中子星-中子星星（NS-NS）合并的动态喷出物。我们研究了从四个NS-NS合并系统喷出的材料的流体动力学模拟的基础上，处理中微子效应在一个精心设计的方式，包括中微子与物质的光学厚区域和光学薄区域的再吸收平衡。我们发现，中子丰富的动态喷出物是显着的合并后残留物发出的中微子的影响，特别是当相比，忽略所有中微子相互作用的情况下。我们的核合成结果表明，产生了一个类似太阳的分布的rprocess元素的质量数A > 1090，包括一个显着的富集Sr和减少生产的锕系元素相比，模拟不包括核子弱过程。动态喷射物质的组成以及相应的放射性衰变加热率被发现是相当独立的系统质量不对称性和所采用的状态方程。这种近似简并的丰度模式和加热速率可以有利于提取的喷出物的性质从kilonova观测，至少如果动力学分量占主导地位的整体喷出物。本工作的第二部分将研究我们的四个NS合并模型的动力学喷出物产生的光变曲线。
We present a coherent study of the impact of neutrino interactions on the r-process element nucleosynthesis and the heating rate produced by the radioactive elements synthesised in the dynamical ejecta of neutron star-neutron star (NS-NS) mergers. We have studied the material ejected from four NS-NS merger systems based on hydrodynamical simulations which handle neutrino effects in an elaborate way by including neutrino equilibration with matter in optically thick regions and re-absorption in optically thin regions. We find that the neutron richness of the dynamical ejecta is significantly affected by the neutrinos emitted by the post-merger remnant, in particular when compared to a case neglecting all neutrino interactions. Our nucleosynthesis results show that a solar-like distribution of rprocess elements with mass numbers A >∼ 90 is produced, including a significant enrichment in Sr and a reduced production of actinides compared to simulations without inclusion of the nucleonic weak processes. The composition of the dynamically ejected matter as well as the corresponding rate of radioactive decay heating are found to be rather independent of the system mass asymmetry and the adopted equation of state. This approximate degeneracy in abundance pattern and heating rates can be favourable for extracting the ejecta properties from kilonova observations, at least if the dynamical component dominates the overall ejecta. Part II of this work will study the light curve produced by the dynamical ejecta of our four NS merger models.