JWST Exoplanetary Worlds and Elemental Survey (JEWELS) II: Condensation Temperature Trends and Galactic Chemical Evolution in JWST Planet-Hosting Stars

TL;DR

This study provides high-precision chemical abundances for 25 JWST exoplanet host stars, analyzing condensation temperature trends and galactic chemical evolution to understand star-planet chemical relationships.

Contribution

It offers a homogeneous stellar abundance catalog for JWST exoplanet hosts, refining elemental abundances and examining GCE and Tcond trends with implications for planet formation.

Findings

No dependence of Tcond slopes on stellar or planetary properties.

Identification of systems with significantly positive or negative Tcond slopes.

Refined carbon and sulfur abundances in cool dwarf stars.

Abstract

We present high-precision chemical abundances for 25 FGK-type stars hosting exoplanets observed in JWST Cycle 3 programs and all GTO and DDT programs from Cycles 1-3, based on high-resolution, high signal-to-noise ratio optical spectra from ground-based telescopes. Using a strictly differential, line-by-line analysis relative to the Sun, we derive homogeneous stellar parameters and abundances for 19 elements with atomic number Z <= 30. The sample spans a wide range of stellar properties, with [Fe/H] = -0.6 to +0.4 dex and effective temperatures between 4700 and 6600 K, and includes hosts of terrestrial and giant planets as well as multi-planet systems. We refine carbon and sulfur abundances in cool dwarfs using spectral synthesis, mitigating systematics from line blending. Several chemically interesting systems are identified, including mildly $\alpha$-enhanced metal-poor stars and multi-planet hosts with elevated [C/O]. Using isochrone ages, we derive empirical Galactic chemical evolution (GCE) relations and examine condensation temperature (Tcond) trends before and after GCE correction. The $T_{cond}$ slopes show no dependence on stellar or planetary properties, indicating that they reflect a mixture of multiple mechanisms, with planet-related signatures entangled in GCE and stellar evolution effects. Thus, Tcond trends require careful interpretation. Several systems with significantly positive or negative Tcond slopes are identified. Together with forthcoming JWST atmospheric measurements, this homogeneous stellar abundance catalog provides a basis for probing star-planet chemical connections and planet formation pathways.