1. Sulphur dioxide in the mid-infrared transmission spectrum of WASP-39b
- Author
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Powell, Diana, Feinstein, Adina D., Lee, Elspeth K. H., Zhang, Michael, Tsai, Shang-Min, Taylor, Jake, Kirk, James, Bell, Taylor, Barstow, Joanna K., Gao, Peter, Bean, Jacob L., Blecic, Jasmina, Chubb, Katy L., Crossfield, Ian J. M., Jordan, Sean, Kitzmann, Daniel, Moran, Sarah E., Morello, Giuseppe, Moses, Julianne I., Welbanks, Luis, Yang, Jeehyun, Zhang, Xi, Ahrer, Eva-Maria, Bello-Arufe, Aaron, Brande, Jonathan, Casewell, S. L., Crouzet, Nicolas, Cubillos, Patricio E., Demory, Brice-Olivier, Dyrek, Achrène, Flagg, Laura, Hu, Renyu, Inglis, Julie, Jones, Kathryn D., Kreidberg, Laura, López-Morales, Mercedes, Lagage, Pierre-Olivier, Valdés, Erik A. Meier, Miguel, Yamila, Parmentier, Vivien, Piette, Anjali A. A., Rackham, Benjamin V., Radica, Michael, Redfield, Seth, Stevenson, Kevin B., Wakeford, Hannah R., Aggarwal, Keshav, Alam, Munazza K., Batalha, Natalie M., Batalha, Natasha E., Benneke, Björn, Berta-Thompson, Zach K., Brady, Ryan P., Caceres, Claudio, Carter, Aarynn L., Désert, Jean-Michel, Harrington, Joseph, Iro, Nicolas, Line, Michael R., Lothringer, Joshua D., MacDonald, Ryan J., Mancini, Luigi, Molaverdikhani, Karan, Mukherjee, Sagnick, Nixon, Matthew C., Oza, Apurva V., Palle, Enric, Rustamkulov, Zafar, Sing, David K., Steinrueck, Maria E., Venot, Olivia, Wheatley, Peter J., and Yurchenko, Sergei N.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The recent inference of sulphur dioxide (SO$_2$) in the atmosphere of the hot ($\sim$1100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations suggests that photochemistry is a key process in high temperature exoplanet atmospheres. This is due to the low ($<$1 ppb) abundance of SO$_2$ under thermochemical equilibrium, compared to that produced from the photochemistry of H$_2$O and H$_2$S (1-10 ppm). However, the SO$_2$ inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.05 $\mu$m, and therefore the detection of other SO$_2$ absorption bands at different wavelengths is needed to better constrain the SO$_2$ abundance. Here we report the detection of SO$_2$ spectral features at 7.7 and 8.5 $\mu$m in the 5-12 $\mu$m transmission spectrum of WASP-39b measured by the JWST Mid-Infrared Instrument (MIRI) Low Resolution Spectrometer (LRS). Our observations suggest an abundance of SO$_2$ of 0.5-25 ppm (1$\sigma$ range), consistent with previous findings. In addition to SO$_2$, we find broad water vapour absorption features, as well as an unexplained decrease in the transit depth at wavelengths longer than 10 $\mu$m. Fitting the spectrum with a grid of atmospheric forward models, we derive an atmospheric heavy element content (metallicity) for WASP-39b of $\sim$7.1-8.0 $\times$ solar and demonstrate that photochemistry shapes the spectra of WASP-39b across a broad wavelength range., Comment: Published in Nature
- Published
- 2024
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