Elemental Abundances of the Super-Neptune WASP-107b's Host Star Using High-resolution, Near-infrared Spectroscopy

Abstract

We present the first elemental abundance measurements of the K dwarf (K7V) exoplanet-host star WASP-107 using high-resolution (R = 45,000), near-infrared (H- and K-band) spectra taken from Gemini-S/IGRINS. We use the previously determined physical parameters of the star from the literature and infer the abundances of 15 elements: C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni, all with precision < 0.1 dex, based on model fitting using MARCS model atmospheres and the spectral synthesis code Turbospectrum. Our results show near-solar abundances and a carbon-to-oxygen ratio (C/O) of 0.50 (+/-0.10), consistent with the solar value of 0.54 (+/-0.09). The orbiting planet, WASP-107b, is a super Neptune with a mass in the Neptune regime (= 1.8 M_Nep) and a radius close to Jupiter's (= 0.94 R_Jup). This planet is also being targeted by four JWST Cycle 1 programs in transit and eclipse, which should provide highly precise measurements of atmospheric abundances. This will enable us to properly compare the planetary and stellar chemical abundances, which is essential in understanding the formation mechanisms, internal structure, and chemical composition of exoplanets. Our study is a proof-of-concept that will pave the way for such measurements to be made for all JWST's cooler exoplanet-host stars.

19 pages, 8 figures, Accepted to ApJ

References in corpus (36)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters
• Can we constrain interior structure of rocky exoplanets from mass and radius measurements?
• Three regimes of extrasolar planets inferred from host star metallicities
• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program II: Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd and Eu
• Line lists for the A2PI-X2Sigma+ (red) and {B2Sigma+-X2Sigma} (violet) Systems of CN, 13C14N, and 12C15N, and Application to Astronomical Spectra
• High-resolution confirmation of an extended helium atmosphere around WASP-107b
• The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with SteParSyn
• Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. II. Test of Theoretical Stellar Isochrones
• WASP-107b's density is even lower: a case study for the physics of planetary gas envelope accretion and orbital migration
• A Super-Solar Metallicity For Stars With Hot Rocky Exoplanets
• The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation
• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program IV. Carbon and C/O ratios for Galactic stellar populations and planet hosts
• Chemical Abundances of M-dwarfs from the APOGEE Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186
• Chemical evidence for planetary ingestion in a quarter of Sun-like stars
• Stellar Characterization of M-dwarfs from the APOGEE Survey: A Calibrator Sample for the M-dwarf Metallicities
• Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances
• A Continuum of Planet Formation Between 1 and 4 Earth Radii
• Elemental Abundances of Kepler Objects of Interest in APOGEE. I. Two Distinct Orbital Period Regimes Inferred from Host Star Iron Abundances
• Polluted White Dwarfs Reveal Exotic Mantle Rock Types on Exoplanets in our Solar Neighborhood
• Detailed Chemical Abundances for a Benchmark Sample of M Dwarfs from the APOGEE Survey
• Evidence that the Hot Jupiter WASP-77 A b Formed Beyond Its Parent Protoplanetary Disk's H2O Ice Line
• Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur
• Host-star and exoplanet compositions: a pilot study usinga wide binary with a polluted white dwarf
• Chemical Abundances in a Sample of Red Giants in the Open Cluster NGC 2420 from APOGEE
• Elemental abundances of nearby M dwarfs based on high-resolution near-infrared spectra obtained by the Subaru/IRD survey: Proof of concept
• Estimating fundamental parameters of nearby M dwarfs from SPIRou spectra
• The AMBRE Project: Origin and evolution of sulfur in the Milky Way
• Near Infrared Spectroscopy of M Dwarfs. I. CO Molecule as an Abundance Indicator of Carbon
• Measuring Elemental Abundances of JWST Target Stars for Exoplanet Characterization I. FGK Stars
• The CARMENES search for exoplanets around M dwarfs: Not-so-fine hyperfine-split vanadium lines in cool star spectra
• A metallicity study of F, G, K and M dwarfs in the Coma Berenices open cluster from the APOGEE survey
• The AMBRE Project: Spectrum normalisation influence on Mg abundances in the metal-rich Galactic disc
• Comparative high-resolution spectroscopy of M dwarfs -- exploring non-LTE effects
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VIII. Carbon and oxygen
• Magnetic Inflation and Stellar Mass. V. Intensification and saturation of M dwarf absorption lines with Rossby number

Cited by in corpus (8)

• A warm Neptune's methane reveals core mass and vigorous atmospheric mixing
• Evidence for Morning-to-Evening Limb Asymmetry on the Cool Low-Density Exoplanet WASP-107b
• Are WASP-107-like Systems Consistent with High-eccentricity Migration?
• Cloud and Haze Parameterization in Atmospheric Retrievals: Insights from Titan's Cassini Data and JWST Observations of Hot Jupiters
• Super-Earth masses and stellar abundances from NIRPS reveal tentative evidence for water-rich formation around M dwarfs
• The Wanderer: Charting WASP-77A b's Formation and Migration Using a System-Wide Inventory of Carbon and Oxygen Abundances
• Confirmation of the hot super-Neptune TOI-672 b with NIRPS and HARPS and Insights into the Neptunian desert around M dwarfs
• TOI-4552 b: A new ultra-short period rocky world revealed by NIRPS and TESS