A new look into the atmospheric composition of WASP-39 b

Fuente: arXiv
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Autores principales: Ma, Sushuang, Saba, Arianna, Al-Refaie, Ahmed Faris, Tinetti, Giovanna, Yurchenko, Sergei N., Tennyson, Jonathan, Pestellini, Cesare Cecchi
Formato: Preprint
Publicado: 2025
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author Ma, Sushuang
Saba, Arianna
Al-Refaie, Ahmed Faris
Tinetti, Giovanna
Yurchenko, Sergei N.
Tennyson, Jonathan
Pestellini, Cesare Cecchi
author_facet Ma, Sushuang
Saba, Arianna
Al-Refaie, Ahmed Faris
Tinetti, Giovanna
Yurchenko, Sergei N.
Tennyson, Jonathan
Pestellini, Cesare Cecchi
contents Being one of the first exoplanets observed by the James Webb Space Telescope, WASP-39 b has become an iconic target and many transit spectra recorded with different instruments (NIRISS, NIRCAM, NIRSpec G395H, NIRSpec PRISM and MIRI) are currently available, allowing in-depth studies of its atmosphere. We present here a novel approach to interpret WASP-39 b's transit spectroscopic data, consisting of a multi-step process where ab initio equilibrium chemistry models and blind retrievals are used iteratively to find physically robust, optimal solutions. Following this approach, we have identified a new scenario to explain WASP-39 b's atmospheric composition, in which silicon-based chemistry plays a major role. In this scenario, SiO may explain the spectral absorption at 4.1 $μ$m, currently interpreted as being due to SO$_2$. SiO and the other gas species identified by the retrieval models, i.e. H$_2$O, CO$_2$, Na and K, are consistent with an atmosphere in chemical equilibrium with a temperature-pressure profile constrained by H$_2$O and CO$_2$ absorption bands. In addition, silicate clouds and hazes can produce the spectral features observed by MIRI in the spectral window 5-12 $μ$m. While we advocate the need for more data, possibly at higher spectral resolution, to confirm our results for WASP-39 b's atmospheric composition, we highlight a refined atmospheric retrieval strategy with pre-selection and post-reconstruction to guide the next generation of transit spectroscopy.
format Preprint
id arxiv_https___arxiv_org_abs_2504_07823
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A new look into the atmospheric composition of WASP-39 b
Ma, Sushuang
Saba, Arianna
Al-Refaie, Ahmed Faris
Tinetti, Giovanna
Yurchenko, Sergei N.
Tennyson, Jonathan
Pestellini, Cesare Cecchi
Earth and Planetary Astrophysics
Being one of the first exoplanets observed by the James Webb Space Telescope, WASP-39 b has become an iconic target and many transit spectra recorded with different instruments (NIRISS, NIRCAM, NIRSpec G395H, NIRSpec PRISM and MIRI) are currently available, allowing in-depth studies of its atmosphere. We present here a novel approach to interpret WASP-39 b's transit spectroscopic data, consisting of a multi-step process where ab initio equilibrium chemistry models and blind retrievals are used iteratively to find physically robust, optimal solutions. Following this approach, we have identified a new scenario to explain WASP-39 b's atmospheric composition, in which silicon-based chemistry plays a major role. In this scenario, SiO may explain the spectral absorption at 4.1 $μ$m, currently interpreted as being due to SO$_2$. SiO and the other gas species identified by the retrieval models, i.e. H$_2$O, CO$_2$, Na and K, are consistent with an atmosphere in chemical equilibrium with a temperature-pressure profile constrained by H$_2$O and CO$_2$ absorption bands. In addition, silicate clouds and hazes can produce the spectral features observed by MIRI in the spectral window 5-12 $μ$m. While we advocate the need for more data, possibly at higher spectral resolution, to confirm our results for WASP-39 b's atmospheric composition, we highlight a refined atmospheric retrieval strategy with pre-selection and post-reconstruction to guide the next generation of transit spectroscopy.
title A new look into the atmospheric composition of WASP-39 b
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2504.07823