How to swallow a planet? Processes and consequences of planet engulfment

by Bárbara Soares (DFA-FCUP, IA-CAUP)

Wednesday 14 May 2025, 14:00 → 15:00 Portugal

Sala de Conferências (Departamento de Física FCTUC)

A protoplanetary disk surrounds newly formed stars. A fraction of this disk material condenses into planet-forming blocks, and most of it eventually accretes onto the star within a few million years, up until the dissipation of the disk. The specific composition of the accreted material may affect the final composition of stars. Accretion of the metal-rich planetary material (i.e., the infall and consequent engulfment of planets) may result in a modification of the stellar surface composition. Moreover, a chemical imprint due to planet engulfment can depend on the disk lifetime and amount of planetary matter, but also on the stellar age, as a large convective layer would prevent an observable change in the stellar composition.

We have analysed the recent data from the New Generation Planetary Population Synthesis (NGPPS) calculations by the Generation III Bern model which simulates the formation and evolution of 1000 planetary systems across 10 Gy. This allows us to study why planetary engulfment happens, when it happens, and what is the composition of engulfed planets.

With this talk, I will present our new findings on the timing, mechanisms, and occurrence rate of planet engulfment around Sun-like stars. I will also discuss the implications of these findings for understanding stellar chemical anomalies.