Expanding the Volatile Abundance Inventory for High-Priority K-Dwarf JWST Exoplanet Systems
Abstract
There are exceedingly few chemical abundance measurements available in the literature for K dwarf stars, especially for those with Teff < 4700 K due to an incompatibility of traditional analyses with their molecular-line-ridden optical spectra. To address the need for K dwarf abundance constraints, we present an elemental ([C/H], [O/H]) and isotopic (12C/13C, 16O/18O) abundance analysis for six K dwarf exoplanet host stars: K2-141, NGTS-10, WASP-43, WASP-69, WASP-80, and HATS-72. Each system hosts an exoplanet targeted by JWST characterization efforts, making host star abundances especially critical as baseline references. Using MARCS model atmospheres, the TurboSpectrum spectral synthesis code, and near-infrared IGRINS spectra, we derive novel [C/H] and [O/H] abundance ratios for these high-priority K dwarf host stars. We further investigate prospects for determining 12C/13C and 16O/18O ratios using 13C16O and 12C18O lines from the 2.3 micron CO bandhead. The observed spectra are too noisy to measure 16O/18O ratios for the sample, but we do find sub-solar 12C/13C ratios for five out of six targets. We also derive uniform gyrochronological ages for each host star to compare with galactic chemical evolution models and identify underlying abundance-age trends. NIR H+K band spectroscopy provides an alternative to optical, atomic line-derived carbon and oxygen abundances for cool dwarf stars. The growing catalog of precise host star elemental and isotopic abundances complements ongoing observations of their companions and provides a baseline for understanding their chemical composition, origin, and evolution.
Related
- Planetesimal Formation Across the Stellar Mass Spectrum and its Influence on Exoplanet-Inherited Volatile Budgets
- Astrometric planet search around southern ultracool dwarfs. V. Discovery of the exoplanet candidate PALTA-1 b
- Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone
- Cloudy mornings and clear evenings on a gas giant exoplanet
- Exoplanet detection through photometric orbital phase modulations
BibTeX
@misc{coria2026expanding,
title = {{Expanding the Volatile Abundance Inventory for High-Priority K-Dwarf JWST Exoplanet Systems}},
author = {David R. Coria and Neda Hejazi and Ian J. M. Crossfield and Ismael Mireles and Casey L. Brinkman and Jared R. Kolecki and Emilio Marfil and Thomas Nordlander and Lauren M. Weiss and Diana Dragomir},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.08676},
eprint = {2611.08676},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.08676},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Expanding the Volatile Abundance Inventory for High-Priority K-Dwarf JWST Exoplanet Systems
AU - David R. Coria
AU - Neda Hejazi
AU - Ian J. M. Crossfield
AU - Ismael Mireles
AU - Casey L. Brinkman
AU - Jared R. Kolecki
AU - Emilio Marfil
AU - Thomas Nordlander
AU - Lauren M. Weiss
AU - Diana Dragomir
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.08676
UR - https://arxiv.org/abs/2611.08676
AB - There are exceedingly few chemical abundance measurements available in the literature for K dwarf stars, especially for those with T_eff < 4700 K due to an incompatibility of traditional analyses with their molecular-line-ridden optical spectra. To address the need for K dwarf abundance constraints, we present an elemental ([C/H], [O/H]) and isotopic (^12C/^13C, ^16O/^18O) abundance analysis for six K dwarf exoplanet host stars: K2-141, NGTS-10, WASP-43, WASP-69, WASP-80, and HATS-72. Each system hosts an exoplanet targeted by JWST characterization efforts, making host star abundances especially critical as baseline references. Using MARCS model atmospheres, the TurboSpectrum spectral synthesis code, and near-infrared IGRINS spectra, we derive novel [C/H] and [O/H] abundance ratios for these high-priority K dwarf host stars. We further investigate prospects for determining ^12C/^13C and ^16O/^18O ratios using ^13C^16O and ^12C^18O lines from the 2.3 micron CO bandhead. The observed spectra are too noisy to measure ^16O/^18O ratios for the sample, but we do find sub-solar ^12C/^13C ratios for five out of six targets. We also derive uniform gyrochronological ages for each host star to compare with galactic chemical evolution models and identify underlying abundance-age trends. NIR H+K band spectroscopy provides an alternative to optical, atomic line-derived carbon and oxygen abundances for cool dwarf stars. The growing catalog of precise host star elemental and isotopic abundances complements ongoing observations of their companions and provides a baseline for understanding their chemical composition, origin, and evolution.
ER -