发表机构
INAF - Osservatorio astronomico di Palermo; Centro de Astrobiología (CAB) CSIC-INTA; University of the Balearic Islands; Universidad de Granada; Instituto de Astrofísica de Canarias（意大利国家天体物理研究所帕勒莫天文台; 西班牙国家航空航天技术研究所/西班牙高等科学研究理事会天体生物学中心; 巴利阿里群岛大学; 格拉纳达大学; 加那利天体物理学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过分析A型和早F型恒星的元素丰度，发现有行星的早F5前辐射型恒星的氧、镍显著超丰，表明其存在岩质碎片吸积，为行星系统化学周期研究提供了关键动力学环节。
AI 中文摘要
气态巨行星-金属丰度关联是理解行星形成的基础。我们以同质方式测定了一批A型和早F型恒星（含与不含已知行星伴星）的金属丰度及各元素丰度，讨论其丰度分布与趋势。我们发现，有行星的恒星通常比无已知行星的恒星具有更高的铁峰元素和挥发性元素丰度，但多数情况下该趋势无统计显著性。两类样本的C/O比值相近，而行星宿主样本的Mg/Si比值向更高值偏移。当样本限定为全辐射型恒星（光谱型早于F5）时，碳元素超丰的统计显著性消失，而氧、镍等元素仍保持显著超丰。该辐射子样本的C/O和Mg/Si比值与对照样本无统计差异。氧和镍的持续超丰，结合全辐射宿主中C/O、Mg/Si比值与无行星恒星相似，表明存在贫挥发分、富硅酸盐的岩质碎片的持续表面污染，而非气态巨行星的吸积。这些发现可能使早型主序星成为行星系统化学生命周期中关键的动力学缺失环节：衔接前主序过渡盘的初始尘埃捕获阶段、完全对流红巨星阶段的表面污染稀释，以及污染白矮星中观测到的小行星物质的最终动力学驱动吸积。
英文摘要
The gas-giant planet-metallicity correlation plays a fundamental role in our understanding of planet formation. We determine in a homogeneous way the metallicity and individual abundances of a sample of A and early-F stars, with and without known planetary companions, and discuss their abundance distribution and trends. We find that stars with planets generally exhibit higher abundances of both iron-peak and volatile elements compared to stars without known planets although in most cases this tendency is not statistically significant. The $\rm {C/O}$ ratio remains similar between both samples, while the $\rm {Mg/Si}$ ratio is shifted towards higher values in the general planet host sample. When the sample is limited to fully radiative stars (spectral type earlier than F5), the statistical significance of carbon overabundances vanishes. In contrast, elements such as O and Ni remain significantly overabundant. The $\rm {C/O}$ and $\rm {Mg/Si}$ ratios in this radiative subsample are statistically indistinguishable from that of the comparison sample. The persistent overabundance of O and Ni, combined with $\rm {C/O}$ and $\rm {Mg/Si}$ ratios similar to those of stars without planets in fully radiative hosts, points to the ongoing surface pollution by volatile-poor, silicate-rich rocky debris, rather than the accretion of gas giants. These findings might position early-type main-sequence stars as a crucial dynamical missing link in the chemical life-cycle of planetary systems: bridging the initial dust-trapping phase in pre-main sequence transition discs, the dilution of this superficial pollution during the fully convective red giant phase, and the eventual dynamically-driven accretion of asteroid material observed in polluted white dwarfs
CommentsAccepted by Astronomy & Astrophysics
