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H_2O_2 within Chaos Terrain on Europa's Leading Hemisphere

Trumbo, Samantha K. and Brown, Michael E. and Hand, Kevin P. (2019) H_2O_2 within Chaos Terrain on Europa's Leading Hemisphere. Astronomical Journal, 158 (3). Art. No. 127. ISSN 1538-3881. doi:10.3847/1538-3881/ab380c.

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Hydrogen peroxide is part of an important radiolytic cycle on Europa and may be a critical source of oxidants to the putative subsurface ocean. The surface geographic distribution of hydrogen peroxide may constrain the processes governing its abundance as well as its potential relevance to the subsurface chemistry. However, maps of Europa's hydrogen peroxide beyond hemispherical averages have never been published. Here, we present spatially resolved L-band (3.16–4 μm) observations of Europa's 3.5 μm hydrogen peroxide absorption, which we obtained using the Near InfraRed Spectrograph (NIRSPEC) and the adaptive optics system on the Keck II telescope. Using these data, we map the strength of the 3.5 μm absorption across the surface at a nominal spatial resolution of ~300 km. Though previous disk-integrated data seemed consistent with the laboratory expectation that Europa's hydrogen peroxide exists primarily in its coldest and iciest regions, we find nearly the exact opposite at this finer spatial scale. Instead, we observe the largest hydrogen peroxide absorptions at low latitudes on the leading and anti-Jovian hemispheres, correlated with chaos terrain, and relative depletions toward the cold, icy high latitudes. This distribution may reflect the effects of decreased hydrogen peroxide destruction due to efficient electron scavenging by CO_2 within chaos terrain.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Trumbo, Samantha K.0000-0002-0767-8901
Brown, Michael E.0000-0002-8255-0545
Hand, Kevin P.0000-0002-3225-9426
Alternate Title:H2O2 within Chaos Terrain on Europa's Leading Hemisphere
Additional Information:© 2019 The American Astronomical Society. Received 2019 May 7; revised 2019 July 26; accepted 2019 July 31; published 2019 August 27. This research was supported by grant 1313461 from the National Science Foundation. This work was also supported by NASA Headquarters under the NASA Earth and Space Science Fellowship Program Grant 80NSSC17K0478. K.P.H. acknowledges support from the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration and funded in part through the internal Research and Technology Development program. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We thank Robert W. Carlson for sharing enlightening details concerning Galileo NIMS observations of CO_2 on Europa. Software: Astropy (Robitaille et al. 2013), skimage.transform (van der Walt et al. 2014).
Group:Astronomy Department
Funding AgencyGrant Number
NASA Earth and Space Science Fellowship80NSSC17K0478
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:planets and satellites: composition – planets and satellites: individual (Europa) – planets and satellites: surfaces
Issue or Number:3
Record Number:CaltechAUTHORS:20190827-102942776
Persistent URL:
Official Citation:Samantha K. Trumbo et al 2019 AJ 158 127
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:98266
Deposited By: Tony Diaz
Deposited On:27 Aug 2019 17:48
Last Modified:16 Nov 2021 17:37

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