Scattering transparency of clouds in exoplanet transit spectra

Jaiswal, B and Robinson, TD (2023) Scattering transparency of clouds in exoplanet transit spectra. In: Monthly Notices of the Royal Astronomical Society, 523 (2). pp. 2809-2817.

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Abstract

The presence of aerosols in an exoplanet atmosphere can veil the underlying material and can lead to a flat transmission spectrum during primary transit observations. In this work, we explore forward scattering effects from supermicron-sized aerosol particles present in the atmosphere of a transiting exoplanet. We find that the impacts of forward scattering from larger aerosols can significantly impact exoplanet transits and the strength of these effects can be dependent on wavelength. In certain cloud configurations, the forward-scattered light can effectively pass through the clouds unhindered, thus rendering the clouds transparent. The dependence of the aerosol scattering properties on wavelength can then lead to a positive slope in the transit spectrum. These slopes are characteristically different from both Rayleigh and aerosol absorption slopes. As examples, we demonstrate scattering effects for both a rocky world and a hot Jupiter. In these models, the predicted spectral slopes due to forward-scattering effects can manifest in the transit spectrum at the level of ∼10-∼100 s of parts per million and, hence, could be observable with NASA's JWST.

Item Type:	Journal Article
Publication:	Monthly Notices of the Royal Astronomical Society
Publisher:	Oxford University Press
Additional Information:	The copyright for this article belongs to the Oxford University Press.
Keywords:	exoplanets; radiative transfer
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	17 Jul 2023 11:15
Last Modified:	17 Jul 2023 11:15
URI:	https://eprints.iisc.ac.in/id/eprint/82450

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