A TENTATIVE IDENTIFICATION OF HCN ICE ON TRITON

Journal Article · Sun Aug 01 00:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/718/2/L53· OSTI ID:21451019

Burgdorf, M ^[1]; Cruikshank, D P; Dalle Ore, C M ^[2]; Sekiguchi, T ^[3]; Nakamura, R ^[4]; Orton, G ^[5]; Quirico, E; Schmitt, B ^[6]

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1. Deutsches SOFIA Institut, Universitaet Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany)
2. NASA Ames Research Center, Mail Stop 245-6, Moffett Field, CA 94035 (United States)
3. Hokkaido University of Education, Hokumon 9, Asahikawa (Japan)
4. GEO Grid Research Group, Information Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Umezono 1-1-1, Tsukuba 305-8568 (Japan)
5. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
6. Laboratoire de Planetologie de Grenoble, Universite Joseph Fourier, Domaine Universitaire, Batiment D de Physique, B.P. 53, 38041 Grenoble Cedex 9 (France)

Spectra of Triton between 1.8 and 5.5 {mu}m, obtained in 2007 May and 2009 November, have been analyzed to determine the global surface composition. The spectra were acquired with the grism and the prism of the Infrared Camera on board AKARI with spectral resolutions of 135 and 22, respectively. The data from 4 to 5 {mu}m are shown in this Letter and compared to the spectra of N{sub 2}, CO, and CO{sub 2}, i.e., all the known ices on this moon that have distinct bands in this previously unexplored wavelength range. We report the detection of a 4{sigma} absorption band at 4.76 {mu}m (2101 cm{sup -1}), which we attribute tentatively to the presence of solid HCN. This is the sixth ice to be identified on Triton and an expected component of its surface because it is a precipitating photochemical product of Triton's thin N{sub 2} and CH{sub 4} atmosphere. It is also formed directly by irradiation of mixtures of N{sub 2} and CH{sub 4} ices. Here we consider only pure HCN, although it might be dissolved in N{sub 2} on the surface of Triton because of the evaporation and recondensation of N{sub 2} over its seasonal cycle. The AKARI spectrum of Triton also covers the wavelengths of the fundamental (1-0) band of {beta}-phase N{sub 2} ice (4.296 {mu}m, 2328 cm{sup -1}), which has never been detected in an astronomical body before, and whose presence is consistent with the overtone (2-0) band previously reported. Fundamental bands of CO and CO{sub 2} ices are also present.

• OSTI ID: 21451019
• Journal Information: Astrophysical Journal Letters, Vol. 718, Issue 2; Other Information: DOI: 10.1088/2041-8205/718/2/L53; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
CARBON DIOXIDE
CARBON MONOXIDE
HYDROCYANIC ACID
METHANE
MOON
PHOTOCHEMISTRY
PLANETARY ATMOSPHERES
PLANETS
TRITONS
ALKANES
ATMOSPHERES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
CHEMISTRY
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SATELLITES
SORPTION