Imaging & Spectroscopy

Detection of Carbon Monoxide in the Atmosphere of WASP-39b Applying Standard Cross-Correlation Techniques to JWST NIRSpec G395H Data

By Keith Cowing
Status Report
September 6, 2023
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Detection of Carbon Monoxide in the Atmosphere of WASP-39b Applying Standard Cross-Correlation Techniques to JWST NIRSpec G395H Data
(a) Cross-correlation function (CCF) of the WASP39b transmission spectrum with the 12C 16O (98.7%) + 13C 16O (1.3%) template. We compare the CCFs resulting from the self cross-correlation of the template (light blue area) and the spectrum (dark blue area), which were scaled arbitrarily. (b) Distribution of the best-fit Gaussian parameters (significance of the central peak, Speak, the central peak velocity, RVpeak, and the FWHM of the distribution of velocities, σRVs) retrieved from the sampled transmission spectra that were randomly generated following a Gaussian distribution centered in the observed transmission spectrum and considering the errors as the Gaussian standard deviation in each point. We performed 30000 iterations. — astro-ph.EP

Carbon monoxide was recently reported in the atmosphere of the hot Jupiter WASP-39b using the NIRSpec PRISM transit observation of this planet, collected as part of the JWST Transiting Exoplanet Community Early Release Science (JTEC ERS) Program.

This detection, however, could not be confidently confirmed in the initial analysis of the higher resolution observations with NIRSpec G395H disperser. Here we confirm the detection of CO in the atmosphere of WASP-39b using the NIRSpec G395H data and cross-correlation techniques. We do this by searching for the CO signal in the unbinned transmission spectrum of the planet between 4.6 and 5.0 μm, where the contribution of CO is expected to be higher than that of other anticipated molecules in the planet’s atmosphere.

Our search results in a detection of CO with a cross-correlation function (CCF) significance of 6.6σ when using a template with only 12C16O lines. The CCF significance of the CO signal increases to 7.5σ when including in the template lines from additional CO isotopologues, with the largest contribution being from 13C16O. Our results highlight how cross-correlation techniques can be a powerful tool for unveiling the chemical composition of exoplanetary atmospheres from medium-resolution transmission spectra, including the detection of isotopologues.

Emma Esparza-Borges, Mercedes López-Morales, Jéa I. Adams Redai, Enric Pallé, James Kirk, Núria Casasayas-Barris, Natasha E. Batalha, Benjamin V. Rackham, Jacob L. Bean, S.L. Casewell, Leen Decin, Leonardo A. Dos Santos, Antonio García Muñoz, Joseph Harrington, Kevin Heng, Renyu Hu, Luigi Mancini, Karan Molaverdikhani, Giuseppe Morello, Nikolay K. Nikolov, Matthew C. Nixon, Seth Redfield, Kevin B. Stevenson, Hannah R. Wakeford, Munazza K. Alam, Björn Benneke, Jasmina Blecic, Nicolas Crouzet, Tansu Daylan, Julie Inglis, Laura Kreidberg, Dominique J.M. Petit dit de la Roche, Jake D. Turner

Comments: Accepted for publication in The Astrophysical Journal Letters
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2309.00036 [astro-ph.EP] (or arXiv:2309.00036v1 [astro-ph.EP] for this version)
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Submission history
From: Emma Esparza-Borges
[v1] Thu, 31 Aug 2023 18:00:00 UTC (6,549 KB)
Astrobiology, Astrochemistry

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻