近日，澳大利亚莫纳什大学的刘凡等人合作并取得一项新进展。经过不懈努力，他们发现，每12颗恒星中至少有一颗存在行星吞噬的现象，从而揭示了相关证据。相关研究成果已于2024年3月20日在国际权威学术期刊《自然》上发表。

该研究团队报道了91对共出生恒星的均匀样本的高精度化学丰度数据，这些样本具有明确的选择函数。研究人员成功识别出至少7个行星摄取的实例，对应的发生率为8%。他们还运用了一个独立的贝叶斯指标，这一工具能有效区分行星特征与其他影响因素，如随机丰度变化和原子扩散。这项研究不仅为行星特征提供了有力证据，而且通过提供对行星吞噬、形成及演化机制的观测约束，促进了人们对恒星-行星-化学联系的更深入理解。

据悉，恒星的化学成分可以通过摄取行星物质和/或行星形成而改变，这将从原恒星盘中去除难熔物质。这些“行星特征”表现为元素丰度差异与尘埃凝结温度之间的相关性。然而，由于未知的发生率、小幅度和恒星年龄差异很大的异质恒星样本，探测这些行星的特征是具有挑战性的。因此，一同诞生的恒星，即共出生恒星，它们的成分是一致的，这一特性对于探测行星的特征非常有利。尽管以往的光谱研究主要局限于少数双星，但盖亚卫星的出现为我们提供了前所未有的机会，它能够在确认为共出生并共同运动的恒星对中探测行星，并进一步揭示其恒星的化学特征。

附：英文原文

Title: At least one in a dozen stars shows evidence of planetary ingestion

Author: Liu, Fan, Ting, Yuan-Sen, Yong, David, Bitsch, Bertram, Karakas, Amanda, Murphy, Michael T., Joyce, Meridith, Dotter, Aaron, Dai, Fei

Issue&Volume: 2024-03-20

Abstract: Stellar chemical compositions can be altered by ingestion of planetary material and/or planet formation, which removes refractory material from the protostellar disk. These ‘planet signatures’ appear as correlations between elemental abundance differences and the dust condensation temperature. Detecting these planet signatures, however, is challenging owing to unknown occurrence rates, small amplitudes and heterogeneous star samples with large differences in stellar ages. Therefore, stars born together (that is, co-natal) with identical compositions can facilitate the detection of planet signatures. Although previous spectroscopic studies have been limited to a small number of binary stars, the Gaia satellite provides opportunities for detecting stellar chemical signatures of planets among co-moving pairs of stars confirmed to be co-natal. Here we report high-precision chemical abundances for a homogeneous sample of ninety-one co-natal pairs of stars with a well defined selection function and identify at least seven instances of planetary ingestion, corresponding to an occurrence rate of eight per cent. An independent Bayesian indicator is deployed, which can effectively disentangle the planet signatures from other factors, such as random abundance variation and atomic diffusion. Our study provides evidence of planet signatures and facilitates a deeper understanding of the star–planet–chemistry connection by providing observational constraints on the mechanisms of planet engulfment, formation and evolution.

DOI: 10.1038/s41586-024-07091-y

Source: https://www.nature.com/articles/s41586-024-07091-y