GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 211-3
Presentation Time: 2:15 PM

SURFACE COMPOSITIONS OF PLUTO AND CHARON


OLKIN, C.B.1, STERN, S.A.2, REUTER, D.C.3, GRUNDY, W.M.4, PROTOPAPA, S.5, SCHMITT, B.6, PHILIPPE, S.6, EARLE, A.M.7, BINZEL, R.P.7, COOK, J.C.1, CRUIKSHANK, D.P.8, DALLE ORE, C.M.8, ENNICO, K.8, WEAVER, H.A.9 and YOUNG, L.A.1, (1)Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302, (2)Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302, (3)NASA Goddard Space Flight Center, Greenbelt, MD, (4)Lowell Observatory, 1400 W. Mars Hill Rd., Flagstaff, AZ 86001, (5)University of Maryland, College Park, MD, (6)Université Grenoble Alpes, CNRS, Grenoble, France, (7)MIT, Cambridge, MA 02139, (8)NASA Ames Research Center, Mountain View, CA 94035, (9)Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, colkin@boulder.swri.edu

On July 14, 2015, the New Horizons spacecraft flew past Pluto providing the first close up look at the surface of Pluto and its moons. One of the main science objectives of the mission is to map the surface compositions of Pluto and Charon (Young, et al. 2008). This was accomplished using the New Horizons Ralph instrument – a combined visible/near infrared multi-spectral imager and a short wavelength infrared spectral imager (Reuter, et al. 2008). The Ralph visible imager (MVIC) has four filters: blue (400-550 nm), red (540-700 nm), near IR (780 – 975 nm) and narrow-band methane (860 – 910 nm) channels. Composition information can be inferred from the surface color and the narrow-band methane filter that is sensitive to the 0.89 um CH4 band. The short wavelength infrared spectral imager covers the spectrally diagnostic wavelength range from 1.25 to 2.5 um with a resolution of 240 and a higher spectral resolution (560) region covering 2.1 to 2.25 um.

From these data, we are able to produce the first composition maps across Pluto and Charon. There are interesting compositional differences across Pluto. The equatorial region has a large red dark band across much of the planet likely the result of non-volatile tholins exposed the surface. This large equatorial band is interrupted by a large glacier called Sputnik Planum (all feature names are informal). The glacial region is composed of N2, CH4 and CO ices. We also see mountain tops in Cthulu Region topped with CH4 ice and the region called Tartarus Dorsa shows interesting “bladed” terrain of roughly north-south aligned ridges with a relief of about 500 meters that is enhanced in CH4 ices.

Compositional maps for Pluto and Charon will be presented.

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