Detection of carbon monoxide's 4.6 micron fundamental band structure in WASP-39b's atmosphere with JWST NIRSpec G395H

Abstract

Carbon monoxide (CO) is predicted to be the dominant carbon-bearing molecule in giant planet atmospheres, and, along with water, is important for discerning the oxygen and therefore carbon-to-oxygen ratio of these planets. The fundamental absorption mode of CO has a broad double-branched structure composed of many individual absorption lines from 4.3 to 5.1 $\mu$m, which can now be spectroscopically measured with JWST. Here we present a technique for detecting the rotational sub-band structure of CO at medium resolution with the NIRSpec G395H instrument. We use a single transit observation of the hot Jupiter WASP-39b from the JWST Transiting Exoplanet Community Early Release Science (JTEC ERS) program at the native resolution of the instrument ($R\sim 2700$) to resolve the CO absorption structure. We robustly detect absorption by CO, with an increase in transit depth of 264 $\pm$ 68 ppm, in agreement with the predicted CO contribution from the best-fit model at low resolution. This detection confirms our theoretical expectations that CO is the dominant carbon-bearing molecule in WASP-39b's atmosphere, and further supports the conclusions of low C/O and super-solar metallicities presented in the JTEC ERS papers for WASP-39b.

arXiv comment11 pages, 5 figures, accepted for publication in ApJL

References in corpus (41)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The chemical composition of the Sun
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• batman: BAsic Transit Model cAlculatioN in Python
• The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope I. Overview of the instrument and its capabilities
• An Infrared Spectroscopic Sequence of M, L and T Dwarfs
• Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere
• Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM
• Retrieving Temperatures and Abundances of Exoplanet Atmospheres with High-Resolution Cross-Correlation Spectroscopy
• Early Release Science of the Exoplanet WASP-39b with JWST NIRSpec G395H
• Photochemically-produced SO${}_2$ in the atmosphere of WASP-39b
• Combining high-dispersion spectroscopy (HDS) with high contrast imaging (HCI): Probing rocky planets around our nearest neighbors
• Early Release Science of the exoplanet WASP-39b with JWST NIRISS
• Detection of carbon monoxide in the high-resolution day-side spectrum of the exoplanet HD 189733b
• Detection of Fe I in the atmosphere of the ultra-hot Jupiter WASP-121b, and a new likelihood-based approach for Doppler-resolved spectroscopy
• Early Release Science of the exoplanet WASP-39b with JWST NIRCam
• Identification of carbon dioxide in an exoplanet atmosphere
• Simultaneous Detection of Water, Methane and Carbon Monoxide in the Atmosphere of Exoplanet HR8799b
• A solar C/O and sub-solar metallicity in a hot Jupiter atmosphere
• Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere
• Carbon monoxide and water vapor in the atmosphere of the non-transiting exoplanet HD 179949 b
• The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b
• Irradiated Planets
• The Stagger-grid: A grid of 3D stellar atmosphere models - IV. Limb darkening coefficients
• WASP-39b: a highly inflated Saturn-mass planet orbiting a late G-type star
• The Transiting Exoplanet Community Early Release Science Program for JWST
• Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program
• Medium-resolution integral-field spectroscopy for high-contrast exoplanet imaging: Molecule maps of the $\beta$ Pictoris system with SINFONI
• The GAPS Programme with HARPS-N at TNG XVI: Measurement of the Rossiter-McLaughlin effect of the transiting planetary systems HAT-P-3, HAT-P-12, HAT-P-22, WASP-39 and WASP-60
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope IV. Capabilities and predicted performance for exoplanet characterization
• Evidence against a strong thermal inversion in HD 209458 b from high-dispersion spectroscopy
• Carbon Dioxide in Exoplanetary Atmospheres: Rarely Dominant Compared to Carbon Monoxide and Water in Hot, Hydrogen-dominated Atmospheres
• No escaping helium from 55 Cnc e
• Molecule mapping of HR8799b using OSIRIS on Keck: Strong detection of water and carbon monoxide, but no methane
• The PHOENIX Exoplanet Retrieval Algorithm and Using H${}^{-}$ Opacity as a Probe in Ultra-hot Jupiters

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