Geological Society of America

T48 Friends of Hoth: Satellites of the Outer Solar System

Sunday, 25 September 2016
1:30 PM - 5:30 PM
Room 201

SPECTRAL ANALYSIS OF PLUTO'S WATER-ICE RICH SPOTS AT NEAR INFRARED WAVELENGTHS

Paper number: T48-3
Program: Technical Sessions
Time: 1:55 PM – 2:10 PM

Authors

J.C. Cook Presenting Author
unaffiliated, Westminster, CO
H.a. Weaver
Johns Hopkins University, Laurel, MD
L.A. Young
Southwest Research Institute, Boulder, CO
B. Schmitt
Université Grenoble Alpes, CNRS, Grenoble
S. Philippe
Université Grenoble Alpes, CNRS, Grenoble
J.A. Stansberry
Space Telescope Science Institute, Baltimore, MD
R.P. Binzel
Massachusetts Institute of Technology, Cambridge, MA
A.M. Earle
Massachusetts Institute of Technology, Cambridge, MA
C.J.Α. Howett
Southwest Research Institute, Boulder, CO
A.H. Parker
Southwest Research Institute, Boulder, CO
A.J. Verbiscer
University of Virginia, Charlottesville, VA
K.N. Singer
Southwest Research Institute, Boulder, CO
D.C. Reuter
NASA Goddard Space Flight Center, Greenbelt, MD
A.W. Lunsford
NASA Goddard Space Flight Center, Greenbelt, MD
D.E. Jennings
NASA Goddard Space Flight Center, Greenbelt, MD
D.P. Cruikshank
NASA Ames Research Center, Moffett Field, CA
C.M. Dalle Ore
NASA Ames Research Center, Moffett Field, CA
C.M. Dalle Ore
SETI Institute, Mountain View, CA
K. Ennico
NASA Ames Research Center, Moffett Field, CA
W.M. Grundy
Lowell Observatory, Flagstaff, AZ
C.B. Olkin
Southwest Research Institute, Boulder, CO
S. Protopapa
University of Maryland, College Park, MD
S. Alan Stern
Southwest Research Institute, Boulder, CO

Abstract

On July 14, 2015, New Horizons used its near-infrared spectral imager, LEISA (Linear Etalon Imaging Spectral Array, Reuter et al., 2008, Space Sci. Rev., 140, 129), to obtain two scans across the encounter hemisphere of Pluto at 6 to 7 km/pixel resolution. These observations mapped the distribution of N₂, CH₄, CO, and H₂O-ice on Pluto’s surface (Grundy et al., 2016, Sci, 351, 9189; Protopapa et al., 2016, Icarus, in review). We have analyzed the H₂O-ice-rich sites across the encounter hemisphere using Hapke theory.

We find that H₂O-ice does not appear in large quantities (>60%) above about 30^◦N. In several locations, such as Viking Terra (all site names used are informal), H₂O-ice appears to be an exposed bedrock layer. Along Virgil Fossa, H₂O-ice appears to be exposed on the north facing scarp, coincident with the greatest elevation difference (1 to 1.5 km) between the north and south sides. H₂O-ice appears for ∼40% of the full length of Virgil Fossa. This is in contrast to other regions of Virgil Fossa which appear to be H₂O and CH₄-ice poor (< 10-15% for each). The terrain to the north (∼50-75 km) and the south (<25 km) of Virgil Fossa nearest the H₂O-ice has similar spectral properties (grain size and abundance) to the scarp, suggesting a relationship. Mass wasting may explain the exposure of H₂O-ice along the scarp, but not in the surrounding area, especially on the higher, southern terrain.

Another site of interest is the region around Pulfrich Crater. The spectrum shows strong crystalline H₂O-ice bands which is not centered on the crater. In addition, this site appears whitish in MVIC enhanced color images, while all other sites appear a distinct red/brown color. In the center of the H₂O-ice-rich spot are a series of 3 or 4 east-west trending pits. Other similarly oriented pit chains in this region, some as close as 75 km away, lack the H₂O-ice signature and appear to be rich in CH₄-ice.

This work was supported by NASA’s New Horizons project.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-287428

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