Chemical signatures of planet engulfment events in Sun-like stars

The observational evidence that planetary systems can be very different from each other, suggests that their dynamical histories were very diverse, probably as a result of a strong sensitivity to the initial conditions. Severe dynamical processes can drive the orbital decay of planets or planetesimals ending in their accretion onto the host star. When this material enters the star, it is rapidly dissolved in the stellar envelope, altering the star's chemical pattern in a way that mirrors the composition observed in rocky objects. Indeed, chemical signatures of planet ingestion has been found in an increasing number of Sun-like stars. These observations carry substantial implications for the field of exoplanet science, as they are entirely detached from both specific biases associated with exoplanet detection techniques and assumptions made in n-body numerical simulations of systems' evolution. For instance, signatures of planet engulfment events suggest that a non-negligible portion of planetary systems has undergone highly dynamic histories, ultimately resulting in the fall of planetary material into the host star. Also, these studies open to the possibility of using chemical abundances of stars to identify which ones are the most likely to host analogues of the calm Solar System.
Comment: To be published in: Handbook of Exoplanets, 2nd Edition, Hans Deeg and Juan Antonio Belmonte (Eds. in Chief), Springer International Publishing AG, part of Springer Nature