Stellar chemical compositions can be altered by ingestion of planetary material^1,2 and/or planet formation, which removes refractory material from the protostellar disk^3,4. These ‘planet signatures’ appear as correlations between elemental abundance differences and the dust condensation temperature^3,5,6. Detecting these planet signatures, however, is challenging owing to unknown occurrence rates, small amplitudes and heterogeneous star samples with large differences in stellar ages^7,8. 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^{9,10,11,12,13}, the Gaia satellite¹⁴ provides opportunities for detecting stellar chemical signatures of planets among co-moving pairs of stars confirmed to be co-natal^15,16. 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 diffusion¹⁷. 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.

^{恒星的化学成分可以通过行星物质1,2}的摄入和/或行星的形成而改变，这会从原恒星盘^3,4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^3,5,6。然而，由于未知的发生率、较小的振幅以及恒星年龄差异较大的异质恒星样本，检测这些行星特征具有挑战性^7,8。因此，具有相同成分的一起诞生（即同生）的恒星可以促进行星特征的检测。尽管之前的光谱研究仅限于少数双星^{9,10,11,12,13}，但盖亚卫星¹⁴提供了在被确认为同生的同生恒星中检测行星化学特征的机会^15,16。在这里，我们报告了九十对同生恒星的同质样本的高精度化学丰度，这些样本具有明确的选择函数，并确定了至少七个行星吞噬的实例，对应于百分之八的发生率。部署了一个独立的贝叶斯指标，它可以有效地将行星特征与其他因素分开，例如随机丰度变化和原子扩散¹⁷。我们的研究提供了行星特征的证据，并通过提供对行星吞噬、形成和演化机制的观测限制，促进了对恒星-行星-化学联系的更深入理解。