Elemental Abundances of JWST’s Cool Host Stars: Searching for Planet-Star Chemical Link

Correlation between the chemical abundances of a planet and its host star provides crucial insight into the planet formation process. The properties of the host star likely influence the protoplanetary disk in which the planets form. In reverse, the accretion of materials from the protoplanetary disk on the host star may also implant disk/planet signature into the host star. JWST is now measuring exoplanet abundances with unprecedented precision, which must be compared to those of their host stars. Although stellar abundances are easily measured for FGK stars, abundances have historically not been measured for cooler dwarfs. However, most exoplanets orbit cool dwarfs, so such systems are the most common end product of the star and planet formation process. This study presents the first detailed elemental abundances of six JWST’s cool host stars (3026 < Teff < 4600 K) by employing their high-resolution (R=45,000), NIR spectra (covering both the H- and K-bands) that we observed using Gemini-S/IGRINS. The abundances are measured based on a line-by-line spectral analysis using MARCS model atmospheres and the spectral synthesis code TurboSpectrum, as described in Hejazi et al. 2023. These stellar abundances can then be compared to those of the relevant planets from the forthcoming JWST spectroscopic analyses, which could reveal fundamental clues on the formation and evolution of exoplanets.