Chemical Abundances for 25 JWST Exoplanet Host Stars with KeckSpec

Abstract

Using a data-driven machine learning tool we report T eff, log ( g ) , v sin ( i ) , and elemental abundances for 15 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Ni, Y) for a sample of 25 exoplanet host stars targeted by JWST's first year of observations. The chemical diversity of these stars show that, while a number of their companion planets may have formed in a disk with chemistry similar to Solar, some JWST targets likely experienced different disk compositions. This sample is part of a larger forthcoming catalog that will report homogeneous abundances of ∼4500 FGK stars derived from Keck/HIRES optical spectra.

WITHDRAWN: The Broadband Transmission Spectrum of WASP-39b from JWST NIRSpec PRISM Observations

“…The bottom panel demonstrates the effect of different atmospheric C/O ratios at 10×Solar metallicity on multiple transmission spectrum models along with the data. Since the star WASP-39 has near-Solar elemental abundances [75] , scaled Solar abundances are a reasonable choice for this star. The CH 4 feature between 3.1-4 µm and 2.2-2.5 µm is very prominent in sub-Solar and Solar metallicity thermochemical equilibrium models shown in Fig.…”

High-resolution atmospheric retrievals of WASP-121b transmission spectroscopy with ESPRESSO: Consistent relative abundance constraints across multiple epochs and instruments

“…The retrieved relative abundance ratios were compared with the relative abundance ratios of WASP-121, calculated using elemental abundances from Polanski et al (2022) and solar elemental abundances from Asplund et al (2009). In the upper left panel of Fig.…”

“…Comparison of the relative abundance constraints from our atmospheric retrievals for each of our observations. The vertical red dotted lines, and the grey shaded regions, represent the relative abundance ratio of WASP-121, and their respective 1𝜎 and 2𝜎 contours, calculated using elemental abundances fromPolanski et al (2022) and solar elemental abundances fromAsplund et al (2009). The literature solar values are log 10 ( 𝜒 Fe /𝜒 Cr ) = 1.86 ± 0.06, log 10 ( 𝜒 Fe /𝜒 V ) = 3.57 ± 0.09, log 10 ( 𝜒 Fe /𝜒 Ti ) = 2.55 ± 0.06, log 10 ( 𝜒 Fe /𝜒 Mg ) = −0.10 ± 0.06, log 10 ( 𝜒 V /𝜒 Ti ) = −1.02 ± 0.09, log 10 ( 𝜒 Fe /𝜒 Na ) = 1.26 ± 0.06, and log 10 ( 𝜒 Fe /𝜒 Ca ) = 1.16 ± 0.06(Asplund et al 2009).…”

A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

“…A detailed interpretation of the atmospheric C/O ratio of WASP-18b would require knowledge of the C/O ratio of the host star. This was recently found to be significantly sub-solar (C/O=0.23±0.05) 28 based on high-resolution spectroscopy. However, stellar C/O measurements are especially challenging due to stellar model inaccuracies and weak/blended absorption lines 34 , so further confirmation is warranted.…”

“…With the wide priors, the HyDRA retrieval infers a H 2 O log mixing ratio of -3.09 +1. 28 −0.32 , with double-peaked posterior probability distributions for the H 2 O and TiO abundances. While the dominant posterior peaks correspond to approximately solar H 2 O and TiO abundances, the second, lower-likelihood peaks correspond to ∼ 30× and ∼ 10 4 × super-solar H 2 O and TiO abundances, respectively.…”