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Detection of hydrogen sulfide above the clouds in Uranus’s atmosphere

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journal contribution
posted on 23.07.2018, 14:53 by Patrick G. J. Irwin, Daniel Toledo, Ryan Garland, Nicholas A. Teanby, Leigh N. Fletcher, Glenn A. Orton, Bruno Bézard
Visible-to-near-infrared observations indicate that the cloud top of the main cloud deck on Uranus lies at a pressure level of between 1.2 bar and 3 bar. However, its composition has never been unambiguously identified, although it is widely assumed to be composed primarily of either ammonia or hydrogen sulfide (H2S) ice. Here, we present evidence of a clear detection of gaseous H2S above this cloud deck in the wavelength region 1.57–1.59 μm with a mole fraction of 0.4–0.8 ppm at the cloud top. Its detection constrains the deep bulk sulfur/nitrogen abundance to exceed unity (>4.4–5.0 times the solar value) in Uranus’s bulk atmosphere, and places a lower limit on the mole fraction of H2S below the observed cloud of ( 1.0 - 2.5 ) ×1 0 - 5 . The detection of gaseous H2S at these pressure levels adds to the weight of evidence that the principal constituent of 1.2–3-bar cloud is likely to be H2S ice.

Funding

We are grateful to the United Kingdom Science and Technology Facilities Council for funding this research and also to our support astronomers: Richard McDermid and Chad Trujillo (2009, 2010). The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministerio da ´ 322 Ciencia e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnolog ˆ ´ıa e Innovacion Productiva (Argentina). ´ We thank Larry Sromovsky for providing the code used to generate our Rayleigh-scattering opacities. Glenn Orton was supported by NASA funding to the Jet Propulsion Laboratory, California Institute of Technology. Leigh Fletcher was supported by a Royal Society Research Fellowship at the University of Leicester

History

Citation

Nature Astronomy, 2018, 2, pp. 420–427

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

AM (Accepted Manuscript)

Published in

Nature Astronomy

Publisher

Nature Publishing Group

eissn

2397-3366

Acceptance date

27/02/2018

Copyright date

2018

Available date

23/10/2018

Publisher version

https://www.nature.com/articles/s41550-018-0432-1

Notes

The file associated with this record is under embargo until 6 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en

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