Scattering transparency of clouds in exoplanet transit spectra

Bhavesh Jaiswal, Tyler D. Robinson

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)2809-2817
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Aug 1 2023


  • exoplanets
  • radiative transfer

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Scattering transparency of clouds in exoplanet transit spectra'. Together they form a unique fingerprint.

Cite this