https://solarsystem.video/videos/watch/43c48c54-c291-43ca-a997-7884303a32db Tom Wilson (University of Warwick). Exoplanets are built from protoplanetary disk ingredients that are thought to be preserved during formation. In small, terrestrial worlds, refractory elements sink to dominate planetary cores and mantles with volatile components potentially producing ocean and atmospheric layers. Thus, natal disk abundance ratios are predicted to influence planetary internal structures. Additionally, varying disk chemistry could alter formation mechanisms via different disk dust-to-gas ratios and surface-densities at crucial radial distances, and overall pebble accretion rates. Post formation, disk composition plays a key role in planet migration due to differing disk drift rates, and planet evolution via varying atmospheric mass-loss properties as a function of metallicity. Tentative evidence of a star-planet composition link exists. If true, this would imply that planets orbiting stars of varying chemistry, in the Milky Way's thick disk, should form and evolve planets differently, also impacting habitability. In this talk, I will review the current state of the field of observationally characterising planetary interiors for worlds around compositionally-diverse stars, and highlight a recent discovery of the first four-planet system spanning the radius valley around a Galactic thick disk M-dwarf. LHS 1903 is orbited by an inner super-Earth and two sub-Neptunes, with a distant fourth world. The inner worlds adhere to planet formation theory, however, the outer planet breaks this trend being smaller, denser, and essentially gas-devoid, rocky body. This finding supports gas-depleted planet formation for M-dwarfs, long-period planets that could imply disk compositional or formation timing effects. I’ll end with a view towards how upcoming missions, such as PLATO, could test formation and evolution pathways by expanding our work to outer regions of Sun-like stars for the first time. Sat, 03 Oct 2026 02:01:08 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://solarsystem.video https://solarsystem.video/client/assets/images/icons/icon-1500x1500.png https://solarsystem.video/videos/watch/43c48c54-c291-43ca-a997-7884303a32db All rights reserved, unless otherwise specified in the terms specified at https://solarsystem.video/about and potential licenses granted by each content's rightholder.