Even faint debris disks can contaminate MIRI exoplanet spectra.
WASP-39b is a gas giant exoplanet orbiting a G-type star, located about 700 light-years away in the constellation Virgo. It has a mass of approximately 0.28 times that of Jupiter and a radius 1.27 times that of Jupiter.
The planet orbits its star every 4.1 days at a distance of 0.0486 AU, with an orbital eccentricity of 0.0. WASP-39b was discovered in 2011 using the transit method and became the first exoplanet to be studied by NASA’s James Webb Space Telescope (JWST) in July 2022.
Atmospheric Composition
Recent observations using JWST have provided detailed insights into the atmospheric composition of WASP-39b. The JWST’s Near InfraRed Spectrograph (NIRSpec) and the Near Infrared Imager and Slitless Spectrograph (NIRISS) have been used to obtain transmission spectra of the planet’s atmosphere.
These observations cover a wavelength range from 0.5 to 5.5 µm and have revealed the presence of various molecules, including water, carbon monoxide, carbon dioxide, sodium , potassium, and sulfur dioxide.
Metallicity and Cloud Properties
The atmospheric studies suggest a heavy-element enhancement, with metallicity estimated to be 10–30 times the solar value. The carbon-to-oxygen (C/O) ratio is sub-solar, while the potassium-to-oxygen (K/O) ratio ranges from solar to super-solar.
The presence of non-grey clouds with inhomogeneous coverage has also been detected, which helps in resolving model degeneracies between cloud properties and atmospheric composition.
Observational Techniques
The observations of WASP-39b have utilized various modes of the JWST instruments, including the NIRSpec PRISM and the NIRISS Single-Object Slitless Spectroscopy (SOSS) mode. These techniques allow for high precision and broad wavelength coverage, which are crucial for characterizing exoplanetary atmospheres.
The detection of CO was confirmed using cross-correlation techniques, highlighting the capabilities of medium-resolution transmission spectra in identifying chemical compositions and isotopologues.
In summary, WASP-39b serves as a significant target for understanding exoplanetary atmospheres, with JWST providing unprecedented detail on its composition and cloud dynamics.
References
Debris Disks Can Contaminate Mid-infrared Exoplanet Spectra: Evidence for a Circumstellar Debris Disk around Exoplanet Host WASP-39
Flagg, Laura ; Weinberger, Alycia J. ; Bell, Taylor J. ; Welbanks, Luis ; Morello, Giuseppe ; Powell, Diana ; Bean, Jacob L. ; Blecic, Jasmina ; Crouzet, Nicolas ; Gao, Peter ; Inglis, Julie ; Kirk, James ; López-Morales, Mercedes ; Molaverdikhani, Karan ; Nikolov, Nikolay ; Oza, Apurva V. ; Rackham, Benjamin V. ; Redfield, Seth ; Tsai, Shang-Min ; Jayawardhana, Ray ; Kreidberg, Laura ; Nixon, Matthew C. ; Stevenson, Kevin B. ; Turner, Jake D.
https://ui.adsabs.harvard.edu/abs/2024ApJ…969L..19F/abstract
Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM
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Detection of Carbon Monoxide in the Atmosphere of WASP-39b Applying Standard Cross-correlation Techniques to JWST NIRSpec G395H Data
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, and Jake D. Turner
https://iopscience.iop.org/article/10.3847/2041-8213/acf27b
Exoplanet Catalog WASP-39 b
https://science.nasa.gov/exoplanet-catalog/wasp-39-b/
Exoplanet WASP-39 b (Transmission Spectra)
https://webbtelescope.org/contents/media/images/2022/060/01GJ3Q66DTT4HPMDCVNC9GXH5Y?news=true
Circular Astronomy 