Motivation
The past decade has transformed how we study the chemical connection between stars and their planets. Large, high-resolution stellar surveys now provide precise elemental abundances for thousands of planet-hosting stars, while HST, JWST, and future missions like ARIEL are delivering atmospheric spectra of unprecedented quality across a wide range of exoplanets. For the first time, we can directly test whether planetary interiors and atmospheres preserve, modify, or erase the chemical fingerprint of their host stars and natal disks.
Recent results show that the star–planet connection is more complex than early models assumed. Stellar abundances are not always a simple proxy for planetary composition: disk evolution, migration, impacts, and atmospheric escape can strongly reshape planetary chemistry. Rocky planets can diverge from stellar Fe/Mg/Si expectations, and atmospheric metallicities and C/O ratios retrieved by JWST do not always follow simple stellar scaling. These findings point to active chemical processing during formation and evolution, not just inheritance.
This splinter session is motivated by the need to move beyond first-order correlations and toward a physically grounded picture that links stellar chemistry, disk evolution, interior structure, and atmospheric measurements. Many of the most important JWST and ARIEL targets orbit cool K and M dwarfs — precisely the stars where abundance measurements are most challenging. Bridging stellar spectroscopy with exoplanet interior and atmospheric modeling is therefore essential for interpreting the next generation of exoplanet data.
Our goal is to bring together experts across stellar abundances, planetary interiors, and atmospheric retrievals to build a chemically self-consistent framework for exoplanet systems. By integrating these perspectives, we aim to clarify when stellar chemistry is predictive, when it breaks down, and how it ultimately shapes the diversity of planetary worlds.