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首页> 外文期刊>The Astrophysical journal >NEUTRON-CAPTURE ELEMENTS IN THE s- AND r-PROCESS-RICH STARS: CONSTRAINTS ON NEUTRON-CAPTURE NUCLEOSYNTHESIS PROCESSES
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NEUTRON-CAPTURE ELEMENTS IN THE s- AND r-PROCESS-RICH STARS: CONSTRAINTS ON NEUTRON-CAPTURE NUCLEOSYNTHESIS PROCESSES

机译：富含s和r过程的恒星中子俘获元素：限制中子俘获核合成过程

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摘要

The chemical abundances of the very metal-poor double-enhanced stars are excellent information for setting new constraints on models of neutron-capture processes at low metallicity. These stars are known as s + r stars, since they show enhancements of both s-process and r-process elements. The observed abundance ratios for the double-enhanced stars can be explained by those of stars that were polluted by an AGB star and subsequently accreted very significant amounts of r-process material out of an AIC (accretion-induced collapse) or Type 1.5 supernova. In this paper we present for the first time an attempt to fit the elemental abundances observed in the s- and r-rich, very metal-poor stars using a parametric model and suggest a new concept of component coefficients to describe the contributions of the individual neutron-capture processes to double-enhanced stars. We find that the abundance ratios of these stars are best fitted by enrichments of s- and r-process material. The overlap factor in the AGB stars where the observed s-process elements were produced lies between 0.1 and 0.81. Taking into account the dependence of the initial-final mass relations on metallicity, this wide range of values could possibly be explained by a wide range of core-mass values of AGB stars at low metallicity. The component coefficient of the r-process is strongly correlated with the component coefficient of the s-process for the double-enhanced stars. This is significant evidence that the r-process material in double-enhanced stars comes from an AIC or Type 1.5 supernova.
机译：极贫金属的双增强恒星的化学丰度是极好的信息，可为低金属度下的中子捕获过程模型设置新的约束。这些恒星被称为s + r恒星，因为它们显示了s过程元素和r过程元素的增强。观测到的双增强恒星的丰度比可以用被AGB恒星污染，然后从AIC（增生引起的坍塌）或1.5型超新星中吸出大量r加工物质的恒星来解释。在本文中，我们首次尝试使用参数模型拟合在富含s和r的金属非常贫乏的恒星中观测到的元素丰度，并提出了一种新的成分系数概念来描述个体的贡献中子捕获过程使恒星倍增。我们发现这些恒星的丰度比最适合通过s和r过程材料的富集。产生观察到的S过程元素的AGB星中的重叠因子在0.1到0.81之间。考虑到初始-最终质量关系对金属性的依赖性，可以用低金属性的AGB恒星的大范围的核心质量值来解释这一宽范围的值。对于双增强星，r过程的成分系数与s过程的成分系数密切相关。这是重要的证据，表明双增强恒星中的r过程物质来自AIC或1.5型超新星。

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