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The Mid-UV Spectrum of Irradiated NaCl at Europa-like Conditions

Brown, Michael E. and Denman, William T. P. and Trumbo, Samantha K. (2022) The Mid-UV Spectrum of Irradiated NaCl at Europa-like Conditions. Planetary Science Journal, 3 (2). Art. No. 28. ISSN 2632-3338. doi:10.3847/psj/ac457f.

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Recent observations from the Hubble Space Telescope show a mid-UV absorption feature localized to leading-hemisphere chaos regions on Europa. The same regions were previously found to have a visible absorption at 450 nm that was attributed to the presence of irradiated NaCl. The lack of any additional diagnostic absorptions for NaCl in the visible spectrum of these terrains made confirmation of this identification difficult. Here we use laboratory experiments to show that NaCl irradiated at Europa’s surface temperatures develops an absorption at ∼220 nm, consistent with the new detection in Europa’s mid-UV spectrum, strongly supporting the NaCl identification. Irradiated NaCl in leading-hemisphere chaos terrain would suggest that sodium and chlorine are important components of Europa’s subsurface ocean.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Brown, Michael E.0000-0002-8255-0545
Denman, William T. P.0000-0003-4752-0073
Trumbo, Samantha K.0000-0002-0767-8901
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 July 30; revised 2021 December 3; accepted 2021 December 21; published 2022 February 2. This research was supported by a grant No. 668346 from the Simons Foundation.
Funding AgencyGrant Number
Simons Foundation668346
Subject Keywords:Europa; Surface composition; Laboratory astrophysics; Ultraviolet astronomy
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Europa (2189); Surface composition (2115); Laboratory astrophysics (2004); Ultraviolet astronomy (1736)
Record Number:CaltechAUTHORS:20220203-318272000
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Official Citation:Michael E. Brown et al 2022 Planet. Sci. J. 3 28
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113256
Deposited By: George Porter
Deposited On:03 Feb 2022 21:53
Last Modified:03 Feb 2022 21:53

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