WASP-39b: exo-Saturn with patchy cloud composition, moderate metallicity, and underdepleted S/O

Fuente: arXiv
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Auteurs principaux: Carone, Ludmila, Lewis, David A., Samra, Dominic, Schneider, Aaron D., Helling, Christiane
Format: Preprint
Publié: 2023
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author Carone, Ludmila
Lewis, David A.
Samra, Dominic
Schneider, Aaron D.
Helling, Christiane
author_facet Carone, Ludmila
Lewis, David A.
Samra, Dominic
Schneider, Aaron D.
Helling, Christiane
contents WASP-39b is one of the first extrasolar giant gas planets that has been observed within the JWST ERS program. Fundamental properties that may enable the link to exoplanet formation differ amongst retrieval methods, for example metallicity and mineral ratios. In this work, the formation of clouds in the atmosphere of WASP-39b is explored to investigate how inhomogeneous cloud properties (particle sizes, material composition, opacity) may be for this intermediately warm gaseous exoplanet. WASP-39b's atmosphere has a comparable day-night temperature median with sufficiently low temperatures that clouds may form globally. The presence of clouds on WASP-39b can explain observations without resorting to a high (> 100x solar) metallicity atmosphere for a reduced vertical mixing efficiency. The assessment of mineral ratios shows an under-depletion of S/O due to condensation compared to C/O, Mg/O, Si/O, Fe/O ratios. Vertical patchiness due to heterogeneous cloud composition challenges simple cloud models. An equal mixture of silicates and metal oxides is expected to characterise the cloud top. Further, optical properties of Fe and Mg silicates in the mid-infrared differ significantly which will impact the interpretation of JWST observations. We conclude that WASP-39b's atmosphere contains clouds and the underdepletion of S/O by atmospheric condensation processes suggest the use of sulphur gas species as a possible link to primordial element abundances. Over-simplified cloud models do not capture the complex nature of mixed-condensate clouds in exoplanet atmospheres. The clouds in the observable upper atmosphere of WASP-39b are a mixture of different silicates and metal oxides. The use of constant particles sizes and/or one-material cloud particles alone to interpret spectra may not be sufficient to capture the full complexity available through JWST observations.
format Preprint
id arxiv_https___arxiv_org_abs_2301_08492
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle WASP-39b: exo-Saturn with patchy cloud composition, moderate metallicity, and underdepleted S/O
Carone, Ludmila
Lewis, David A.
Samra, Dominic
Schneider, Aaron D.
Helling, Christiane
Earth and Planetary Astrophysics
WASP-39b is one of the first extrasolar giant gas planets that has been observed within the JWST ERS program. Fundamental properties that may enable the link to exoplanet formation differ amongst retrieval methods, for example metallicity and mineral ratios. In this work, the formation of clouds in the atmosphere of WASP-39b is explored to investigate how inhomogeneous cloud properties (particle sizes, material composition, opacity) may be for this intermediately warm gaseous exoplanet. WASP-39b's atmosphere has a comparable day-night temperature median with sufficiently low temperatures that clouds may form globally. The presence of clouds on WASP-39b can explain observations without resorting to a high (> 100x solar) metallicity atmosphere for a reduced vertical mixing efficiency. The assessment of mineral ratios shows an under-depletion of S/O due to condensation compared to C/O, Mg/O, Si/O, Fe/O ratios. Vertical patchiness due to heterogeneous cloud composition challenges simple cloud models. An equal mixture of silicates and metal oxides is expected to characterise the cloud top. Further, optical properties of Fe and Mg silicates in the mid-infrared differ significantly which will impact the interpretation of JWST observations. We conclude that WASP-39b's atmosphere contains clouds and the underdepletion of S/O by atmospheric condensation processes suggest the use of sulphur gas species as a possible link to primordial element abundances. Over-simplified cloud models do not capture the complex nature of mixed-condensate clouds in exoplanet atmospheres. The clouds in the observable upper atmosphere of WASP-39b are a mixture of different silicates and metal oxides. The use of constant particles sizes and/or one-material cloud particles alone to interpret spectra may not be sufficient to capture the full complexity available through JWST observations.
title WASP-39b: exo-Saturn with patchy cloud composition, moderate metallicity, and underdepleted S/O
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2301.08492