METHANE AND NITROGEN ABUNDANCES ON PLUTO AND ERIS

Journal Article · Fri Dec 10 04:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/725/1/1296· OSTI ID:21474353

Tegler, S C; Cornelison, D M; Abernathy, M R; Bovyn, M J; Burt, J A; Evans, D E; Maleszewski, C K; Thompson, Z ^[1]; Grundy, W M ^[2]; Romanishin, W ^[3]; Vilas, F ^[4]

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1. Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ 86011 (United States)
2. Lowell Observatory, Flagstaff, AZ 86001 (United States)
3. Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)
4. MMT Observatory, University of Arizona, Tucson, AZ 85721 (United States)

We present spectra of Eris from the MMT 6.5 m Telescope and Red Channel Spectrograph (5700-9800 A, 5 A pixel{sup -1}) on Mt. Hopkins, AZ, and of Pluto from the Steward Observatory 2.3 m Telescope and Boller and Chivens Spectrograph (7100-9400 A, 2 A pixel{sup -1}) on Kitt Peak, AZ. In addition, we present laboratory transmission spectra of methane-nitrogen and methane-argon ice mixtures. By anchoring our analysis in methane and nitrogen solubilities in one another as expressed in the phase diagram of Prokhvatilov and Yantsevich, and comparing methane bands in our Eris and Pluto spectra and methane bands in our laboratory spectra of methane and nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are {approx}10% and {approx}90% and Pluto's bulk methane and nitrogen abundances are {approx}3% and {approx}97%. Such abundances for Pluto are consistent with values reported in the literature. It appears that the bulk volatile composition of Eris is similar to the bulk volatile composition of Pluto. Both objects appear to be dominated by nitrogen ice. Our analysis also suggests, unlike previous work reported in the literature, that the methane and nitrogen stoichiometry is constant with depth into the surface of Eris. Finally, we point out that our Eris spectrum is also consistent with a laboratory ice mixture consisting of 40% methane and 60% argon. Although we cannot rule out an argon-rich surface, it seems more likely that nitrogen is the dominant species on Eris because the nitrogen ice 2.15 {mu}m band is seen in spectra of Pluto and Triton.

• OSTI ID: 21474353
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 725; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
ALKANES
ARGON
ASTROPHYSICS
DIAGRAMS
ELEMENTS
FLUIDS
GASES
HYDROCARBONS
ICE
INFORMATION
METHANE
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
PHASE DIAGRAMS
PHYSICS
PLANETS
PLUTO PLANET
RARE GASES
STOICHIOMETRY
TELESCOPES