KECK II OBSERVATIONS OF HEMISPHERICAL DIFFERENCES IN H{sub 2}O{sub 2} ON EUROPA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
We present results from Keck II observations of Europa over four consecutive nights using the near-infrared spectrograph. Spectra were collected in the 3.14-4.0 {mu}m range, enabling detection and monitoring of the 3.5 {mu}m feature due to hydrogen peroxide. Galileo Near-Infrared Mapping Spectrometer results first revealed hydrogen peroxide on Europa in the anti-Jovian region of the leading hemisphere at a percent by number abundance of 0.13% {+-} 0.07% relative to water. We find comparable results for the two nights over which we observed the leading hemisphere. Significantly, we observed a small amount of hydrogen peroxide ({approx}0.04%) during observations of Europa's anti-Jovian and sub-Jovian hemispheres. Almost no hydrogen peroxide was detected during observations of just the trailing hemisphere. We conclude that the Galileo observations likely represent the maximum hydrogen peroxide concentration, the exception potentially being the cold water ice regions of the poles, which are not readily observable from the ground. Our mapping of the peroxide abundance across Europa requires revisions to previous estimates for Europa's global surface abundance of oxidants and leads to a reduction in the total oxidant delivery expected for the subsurface ocean if an exchange of surface material with the ocean occurs.
- OSTI ID:
- 22130770
- Journal Information:
- Astrophysical Journal Letters, Vol. 766, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
A New Spectral Feature on the Trailing Hemisphere of Europa at 3.78 μm
SPATIALLY RESOLVED SPECTROSCOPY OF EUROPA’S LARGE-SCALE COMPOSITIONAL UNITS AT 3–4 μ m WITH KECK NIRSPEC