Sulfur Hazes in Giant Exoplanet Atmospheres: Impacts on Reflected Light Spectra
- NASA Ames Research Center, Moffett Field, CA 94035 (United States)
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA 95064 (United States)
Recent work has shown that sulfur hazes may arise in the atmospheres of some giant exoplanets, due to the photolysis of H{sub 2}S. We investigate the impact such a haze would have on an exoplanet’s geometric albedo spectrum and how it may affect the direct imaging results of the Wide Field Infrared Survey Telescope ( WFIRST ), a planned NASA space telescope. For temperate (250 K < T {sub eq} < 700 K) Jupiter-mass planets, photochemical destruction of H{sub 2}S results in the production of ∼1 ppmv of S{sub 8} between 100 and 0.1 mbar, which, if cool enough, will condense to form a haze. Nominal haze masses are found to drastically alter a planet’s geometric albedo spectrum: whereas a clear atmosphere is dark at wavelengths between 0.5 and 1 μ m, due to molecular absorption, the addition of a sulfur haze boosts the albedo there to ∼0.7, due to scattering. Strong absorption by the haze shortward of 0.4 μ m results in albedos <0.1, in contrast to the high albedos produced by Rayleigh scattering in a clear atmosphere. As a result, the color of the planet shifts from blue to orange. The existence of a sulfur haze masks the molecular signatures of methane and water, thereby complicating the characterization of atmospheric composition. Detection of such a haze by WFIRST is possible, though discriminating between a sulfur haze and any other highly reflective, high-altitude scatterer will require observations shortward of 0.4 μ m, which is currently beyond WFIRST ’s design.
- OSTI ID:
- 22663741
- Journal Information:
- Astronomical Journal (Online), Vol. 153, Issue 3; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
Optical Transmission Spectroscopy of the Terrestrial Exoplanet LHS 3844b from 13 Ground-based Transit Observations
Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets