Optical properties of potential condensates in exoplanetary atmospheres

Kitzmann, Daniel; Heng, Kevin (2018). Optical properties of potential condensates in exoplanetary atmospheres. Monthly notices of the Royal Astronomical Society, 475(1), pp. 94-107. Oxford University Press 10.1093/mnras/stx3141

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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 MIEVO code as well as previous studies. Secondly, 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 extinction 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 per cent. 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. The compilation of the optical constants and LX-MIE is publicly available as part of the open-source Exoclime Simulation Platform (http://www.exoclime.org).

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Kitzmann, Daniel and Heng, Kevin

Subjects:

500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0035-8711

Publisher:

Oxford University Press

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

03 Jun 2019 10:27

Last Modified:

03 Jun 2019 10:27

Publisher DOI:

10.1093/mnras/stx3141

BORIS DOI:

10.7892/boris.126843

URI:

https://boris.unibe.ch/id/eprint/126843

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