Optical properties of potential condensates in exoplanetary atmospheres

Daniel Kitzmann, Kevin Heng
(Submitted on 13 Oct 2017)

The prevalence of clouds in currently observable exoplanetary atmospheres motivates the compilation and calculation of their optical properties. First, we present a new open-source Mie scattering code known as LX-MIE, which is able to consider large size parameters (∼107) using a single computational treatment. We validate LX-MIE against the classical MIEV0 code as well as previous studies. Second, we embark on an expanded survey of the published literature for both the real and imaginary components of the refractive indices of 32 condensate species. As much as possible, we rely on experimental measurements of the refractive indices and resort to obtaining the real from the imaginary component (or vice versa), via the Kramers-Kronig relation, only in the absence of data. We use these refractive indices as input for LX-MIE to compute the absorption, scattering and efficiency efficiencies of all 32 condensate species. Finally, we use a three-parameter function to provide convenient fits to the shape of the extinction efficiency curve. We show that the errors associated with these simple fits in the Wide Field Camera 3 (WFC3), J, H and K wavebands are ∼10%. These fits allow for the extinction cross section or opacity of the condensate species to be easily included in retrieval analyses of transmission spectra. We discuss prospects for future experimental work.

Comments:    14 pages, 5 figures, 3 tables
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP)
Cite as:    arXiv:1710.04946 [astro-ph.EP] (or arXiv:1710.04946v1 [astro-ph.EP] for this version)
Submission history
From: Daniel Kitzmann
[v1] Fri, 13 Oct 2017 14:48:54 GMT (733kb,D)
https://arxiv.org/abs/1710.04946