Cloud base signature in transmission spectra of exoplanet atmospheres

Sanaz Vahidinia, Jeffrey N. Cuzzi, Mark Marley, Jonathan Fortney

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


We present an analytical model for the transmission spectrum of a transiting exoplanet, showing that a cloud base can produce an observable inflection point in the spectrum. The wavelength and magnitude of the inflection can be used to break the degeneracy between the atmospheric pressure and the abundance of the main cloud material, however, the abundance still depends on cloud particle size. An observed inflection also provides a specific point on the atmospheric P-T profile, giving us a "thermometer" to directly validate or rule out postulated cloud species. We apply the model to the transit spectrum of HD 189733b.

Original languageEnglish (US)
Article numberL11
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Jul 1 2014
Externally publishedYes


  • methods: analytical
  • planets and satellites: atmospheres
  • radiative transfer
  • scattering

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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