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

This paper includes data gathered with the 6.5 metre Magellan Telescope located at Las Campanas Observatory, Chile. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W. M. Keck Foundation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 108.22EC.001. This research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. Y.-S.T. acknowledges financial support from the Australian Research Council through DECRA Fellowship DE220101520. M.T.M. acknowledges the support of the Australian Research Council through Future Fellowship grant FT180100194. B.B. thanks the European Research Council (ERC Starting Grant 757448-PAMDORA) for their financial support. M.J. gratefully acknowledges funding of MATISSE: Measuring Ages Through Isochrones, Seismology, and Stellar Evolution, awarded through the European Commission’s Widening Fellowship. This project has received funding from the European Union’s Horizon 2020 research and innovation programme. We thank A. Ji for offering advice on data collection and preparation; and S. Campbell, A. Mustill and Q. Sun for discussions. The C3PO programme is made possible through the Carnegie Observatories’ support and allocation of observation time on the Magellan Telescope. We recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.

The spectral data underlying this article are available in Keck Observatory Archive (https://koa.ipac.caltech.edu/cgi-bin/KOA/nph-KOAlogin) and the European Southern Observatory Science Archive Facility (http://archive.eso.org/eso/eso_archive_main.html). They can be accessed with Keck Program ID W244Hr (semester: 2021B, principal investigator F.L.) and European Southern Observatory Programme ID 108.22EC.001 (principal investigator D.Y.), respectively. The spectra from the Magellan Telescope can be shared upon request to the corresponding author. The rest of data underlying this article are available in the article and its Supplementary Information.

Extended Data Fig. 1 A portion of the reduced spectra of an example co-moving pair of stars (HD 185726/185689; Pair 124).

Extended Data Fig. 2 Comparison of abundance results.

The stellar line analysis program MOOG is available at https://www.as.utexas.edu/~chris/moog.html. The stellar model atmospheres are available at http://kurucz.harvard.edu/grids.html. The code for equivalent width measurements is very similar to REVIEW, which is provided in https://github.com/madeleine-mckenzie/REvIEW. The Bayesian modelling program DYNESTY is available at https://github.com/joshspeagle/dynesty.

The authors declare no competing interests.