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arXiv 2303.00765astro-ph.HEastro-ph.SR
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致密天体外流中的核合成及相关千新星的探测前景

Nucleosynthesis in outflows of compact objects and detection prospects of associated kilonovae

Nick Ekanger, Mukul Bhattacharya, Shunsaku Horiuchi

AI总结:

本研究对比三类天体的核合成产额,明确r过程元素的主要来源,同时给出MR CCSNe的事件率上限,并预测LSST依托引力波触发每年可探测的千新星事件数量。

摘要:

我们对双中子星(BNS)并合、黑洞-中子星(BHNS)并合以及核坍缩超新星(CCSNe)的核合成产额开展了对比分析,旨在确定哪些是恒星中观测到的r过程元素增丰的最主要来源。我们发现,在计入体积事件率后,BNS和BHNS双星在并合后可能抛射出质量分布相近的稳定r过程核(直至第三峰和锕系元素,质量数A约为200-240)。磁旋转(MR)型CCSNe可能经历弱r过程(直至A约为140),并对轻元素原初过程(LEPP)核的产生有贡献,而典型的热驱动、中微子驱动型CCSNe仅能合成直至第一r过程峰的核(A约为80-90)。我们还发现,MR CCSNe的事件率上限不超过典型热型CCSNe事件率的1%;如果该比率更高,弱r过程核将会被过量产生。尽管最大的不确定性来自体积事件率,但未来几年借助即将开展的巡天项目确认这些事件率的前景十分可观。我们使用一个简单模型估算并合产生的千新星光变曲线,并结合我们的一组基准并合参数预测:在有引力波(GW)前置触发的情况下,Vera C. Rubin天文台(LSST)每年可探测到约7次BNS事件和约2次BHNS事件。

英文摘要:

We perform a comparative analysis of nucleosynthesis yields from binary neutron star (BNS) mergers, black hole-neutron star (BHNS) mergers, and core-collapse supernovae (CCSNe) with the goal of determining which are the most dominant sources of r-process enrichment observed in stars. We find that BNS and BHNS binaries may eject similar mass distributions of robust r-process nuclei post merger (up to 3rd peak and actinides, $A\sim200-240$), after accounting for the volumetric event rates. Magnetorotational (MR) CCSNe likely undergo a weak r-process (up to $A\sim140$) and contribute to the production of light element primary process (LEPP) nuclei, whereas typical thermal, neutrino-driven CCSNe only synthesize up to 1st r-process peak nuclei ($A\sim80-90$). We also find that the upper limit to the rate of MR CCSNe is $\lesssim1\%$ the rate of typical thermal CCSNe; if the rate was higher, then weak r-process nuclei would be overproduced. Although the largest uncertainty is from the volumetric event rate, the prospects are encouraging for confirming these rates in the next few years with upcoming surveys. Using a simple model to estimate the resulting kilonova light curve from mergers and our set of fiducial merger parameters, we predict that $\sim7$ BNS and $\sim2$ BHNS events will be detectable per year by the Vera C. Rubin Observatory (LSST), with prior gravitational wave (GW) triggers.

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。

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