太阳孪生星/相似星周围的行星（PASTA）III：含行星太阳相似星中的化学时钟关系

中文摘要 AI 辅助

背景。在不同核合成时标上合成的元素之间的丰度比提供了估算恒星年龄的经验化学时钟，但稳健的校准需要具有精确恒星参数和元素丰度的均匀样本。目的。我们旨在研究行星的存在是否改变经验化学时钟关系。方法。我们给出了用Keck/HIRES、LBT/PEPSI和Subaru/HDS观测的52个新的含行星目标的精确恒星参数和元素丰度。结合PASTA I和II，完整样本包含94颗恒星，其中81颗被识别为含行星的太阳孪生星和相似星，并用于刻画银河系化学演化以及推导经验化学时钟关系。结果。我们恢复了预期的银河系化学演化趋势，其中α元素如Mg和S随恒星年龄增加而增加，而慢中子俘获过程元素如Y、Ba和Sr则呈现负的年龄相关性。相比之下，铁峰元素和快中子俘获过程元素Eu几乎没有或没有显著的年龄依赖性。这些趋势产生了基于[Y/Mg]、[Y/Al]、[Ba/Mg]、[Ba/Al]和[Sr/Mg]的紧密化学时钟关系，其中[Y/Mg]和[Y/Al]提供了最强的相关性。[Ba/Al]显示出最陡的年龄依赖性，且基于Ba的比率通常比基于Y的对应比率对年龄更敏感。结论。含行星的太阳相似星遵循与邻近太阳孪生星一致的化学时钟关系，没有证据表明存在显著的行星相关效应。推导出的关系主要适用于银河系薄盘中的本地太阳孪生星和相似星。

英文摘要

Context. Abundance ratios between elements synthesized on different nucleosynthetic timescales provide empirical chemical clocks for estimating stellar ages, but robust calibrations require homogeneous samples with precise stellar parameters and elemental abundances. Aims. We aim to investigate whether the presence of planets modifies empirical chemical clock relations. Methods. We present high-precision stellar parameters and elemental abundances for 52 new planet-hosting targets observed with Keck/HIRES, LBT/PEPSI, and Subaru/HDS. Combined with PASTA I and II, the full sample comprises 94 stars, of which 81 are identified as planet-hosting solar twins and analogs, and is used to characterize Galactic chemical evolution and derive empirical chemical clock relations. Results. We recover the expected Galactic chemical evolution trends, with $α$-elements such as Mg and S increasing with stellar age, while s-process elements such as Y, Ba, and Sr show negative age correlations. In contrast, Fe-peak elements and the r-process element Eu show little or no significant age dependence. These trends give rise to tight chemical clock relations based on [Y/Mg], [Y/Al], [Ba/Mg], [Ba/Al], and [Sr/Mg], with [Y/Mg] and [Y/Al] providing the strongest correlations. [Ba/Al] shows the steepest age dependence, and the Ba-based ratios are generally more sensitive to age than their Y-based counterparts. Conclusions. Planet-hosting solar analogs follow chemical-clock relations consistent with those of nearby solar twins, with no evidence for a significant planet-related effect. The derived relations are primarily applicable to local solar twins and analogs in the Galactic thin disk.

发表机构

• Tsung-Dao Lee Institute, School of Physics and Astronomy, & State Key Laboratory of Dark Matter Physics, Shanghai Jiao Tong University（上海交通大学李政道研究所、物理与天文学院及暗物质物理国家重点实验室）
• Department of Astronomy, The Ohio State University（俄亥俄州立大学天文学系）
• Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University（俄亥俄州立大学宇宙学与粒子天体物理学中心）
• Department of Astronomy, Tsinghua University（清华大学天文学系）
• Institute for Astronomy, University of Hawai‘i（夏威夷大学天文学研究所）

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11 pages; accepted in Astronomy & Astrophysics