AI 中文总结
研究利用贝叶斯框架，基于核合成计算，通过MCMC采样器拟合恒星丰度，推断r过程天体物理条件，发现HD222925等恒星丰度可用两个成分再现，强调结合二者约束条件的力量及对观测和核物理输入改进的推动。
AI 中文摘要
在贫金属、r过程增强的恒星中观测到的重元素丰度，提供了关于快速中子俘获过程（r过程）发生的天体物理条件的独特信息。我们提出了一个贝叶斯框架，从恒星丰度模式推断这些条件。基于一个大型的与观测地点无关的r过程调查，我们使用马尔可夫链蒙特卡罗（MCMC）采样器，将观测到的丰度与核合成计算的丰度加权叠加进行拟合，每个丰度由初始电子分数、熵和膨胀时间尺度参数化。将这个框架应用于几乎完整的r过程模板星HD222925，我们发现需要两个成分：一个较重的H成分产生从第二到第三峰的元素，一个较轻的L成分产生从第一到第二峰的元素。增加成分数量并不能显著改善与观测的一致性。将分析扩展到有限r过程的恒星HD128279和HD122563，以及太阳r过程残余物，我们发现它们的丰度几乎可以由相同的两个成分再现，尽管相对权重不同。此外，太阳中最轻的中子俘获元素（$Z \lesssim 35$）需要HD222925中不存在的额外贡献。残余差异集中在对观测系统误差敏感的元素（如Ag和Cd）或核物理输入（在第三峰附近）。我们的研究强调了将恒星丰度与核合成计算相结合以约束r过程天体物理条件的力量，并推动了观测数据和核物理输入的进一步改进。
英文摘要
The abundances of heavy elements observed in metal-poor, r-process-enhanced stars provide unique information about the astrophysical conditions in which the rapid neutron-capture process (r-process) occurs. We present a Bayesian framework to infer these conditions from stellar abundance patterns. Building on a large site-independent r-process survey, we use a Markov chain Monte Carlo (MCMC) sampler to fit observed abundances with weighted superpositions of abundances from nucleosynthesis calculations, each parameterized by an initial electron fraction, entropy, and expansion timescale. Applying this framework to the nearly complete r-process template star HD222925, we find that two components are required: A heavier H-component producing elements from the second to the third peak and a lighter L-component producing elements from the first to the second peak. Increasing the number of components does not significantly improve the agreement with observations. Extending the analysis to the limited-r stars HD128279 and HD122563, and to the solar r-process residuals, we find that their abundances can be reproduced by almost the same two components, albeit with different relative weights. Moreover, the lightest neutron-capture elements ($Z \lesssim 35$) in the Sun require additional contributions absent in HD222925. Residual discrepancies are concentrated in elements sensitive to observational systematics (e.g., Ag and Cd) or nuclear-physics inputs (around the third peak). Our study highlights the power of combining stellar abundances with nucleosynthesis calculations to constrain the astrophysical conditions of the r-process, and motivates further improvements in both observational data and nuclear-physics inputs.
Comments16 pages, 8 figures
