Search for Nonmethane Hydrocarbons on Pluto

Sasaki, Takanori; Kanno, Ai; Ishiguro, Masateru; Kinoshita, Daisuke; Nakamura, Ryosuke

doi:10.1086/427553

Cited by 21 publications

(18 citation statements)

References 41 publications

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“…The best agreement with the data was obtained with a ternary mixture of C 2 H 2 :C 2 H 6 and CH 4 with mass ratios 1:1:10, but the narrow absorption feature of C 2 H 6 at 3.65 lm is not present in the data. Olkin et al (2007) reported observations of Pluto from 1.0 to 4.2 lm and did not find any evidence of non-methane hydrocarbons although their spectrum differed from that of Sasaki et al (2005). Differences in the spectra by Olkin et al and Sasaki et al may be explained by the fact that the central meridian longitudes represented by their observations differ by 145°.…”

Section: Introductionmentioning

confidence: 82%

“…Later, Sasaki et al (2005) analyzed spectra of Pluto at longer wavelengths (2.9-3.9 lm) and showed that the addition of nonmethane hydrocarbons could improve the model fits to the data, but there was no clear identification. The best agreement with the data was obtained with a ternary mixture of C 2 H 2 :C 2 H 6 and CH 4 with mass ratios 1:1:10, but the narrow absorption feature of C 2 H 6 at 3.65 lm is not present in the data.…”

Section: Introductionmentioning

confidence: 99%

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A search for ethane on Pluto and Triton

DeMeo

Dumas²,

Bérgh

et al. 2010

Icarus

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

A search for ethane on Pluto and Triton

DeMeo

Dumas²,

Bérgh

et al. 2010

Icarus

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“…High-energy electrons produced from Saturn's magnetosphere could be partly responsible for the production of these molecules (Cravens et al 2005). Sasaki et al (2005) recently conducted a search for nonmethane hydrocarbons on Pluto and found absorptions at 3.10, 3.22, and 3.35 m (3225, 3125, and 2985 cm À1 ), whereby the peak at 3.22 m seems to be indicative of the presence of ethylene. Vernazza et al (2005) reported the presence of features appearing at 3.42 m (2920 cm À1 ) and 3.06 m (3268 cm À1 ) on the surface of the asteroid 1 Ceres, which may be indicative of the presence of ethane and acetylene, respectively.…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

Laboratory Studies on the Irradiation of Methane in Interstellar, Cometary, and Solar System Ices

Bennett

Jamieson

Osamura

et al. 2006

ApJ

157

168

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Pure methane ices (CH 4 ) were irradiated at 10 K with energetic electrons to mimic the energy transfer processes that occur in the track of the trajectories of MeV cosmic-ray particles. The experiments were monitored via an FTIR spectrometer (solid state) and a quadrupole mass spectrometer (gas phase). Combined with electronic structure calculations, this paper focuses on the identification of CH x (x ¼ 1Y4) and C 2 H x (x ¼ 2Y6) species and also investigates their formation pathways quantitatively. The primary reaction step is determined to be the cleavage of a carbonhydrogen bond of the methane molecule to form a methyl radical (CH 3 ) plus a hydrogen atom. Hydrogen atoms recombined to form molecular hydrogen, the sole species detected in the gas phase during the irradiation exposure. In the matrix two neighboring methyl radicals can recombine to form an internally excited ethane molecule (C 2 H 6 ), which either can be stabilized by the surrounding matrix or was found to decompose unimolecularly to the ethyl radical (C 2 H 5 ) plus atomic hydrogen and then to the ethylene molecule (C 2 H 4 ) plus molecular hydrogen. The initially synthesized ethane, ethyl, and ethylene molecules can be radiolyzed subsequently by the impinging electrons to yield the vinyl radical (C 2 H 3 ) and acetylene (C 2 H 2 ) as degradation products. Upon warming the ice sample after the irradiation, the new species are released into the gas phase, simulating the sublimation processes interstellar ices undergo during the hot core phase or comets approaching perihelion. Our investigations also aid the understanding of the synthesis of hydrocarbons likely to be formed in the aerosol particles and organic haze layers of hydrocarbon-rich atmospheres of planets and their moons such as Titan.

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“…These non-volatile ices may subsequently be covered over time by deposition of volatiles onto the surface. Sasaki et al (2005) Grundy et al, 2010, respectively). Additionally, Cruikshank et al (2006) argue, based on currently unpublished CO laboratory data, that the contribution of 13 CO is negligible and that the 2.405 lm feature is almost entirely due to ethane absorption.…”

Section: Introductionmentioning

confidence: 97%

Evidence for longitudinal variability of ethane ice on the surface of Pluto

Holler¹,

Young²,

Grundy³

et al. 2014

Icarus

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a b s t r a c tWe present the results of an investigation using near-infrared spectra of Pluto taken on 72 separate nights using SpeX/IRTF. These data were obtained between 2001 and 2013 at various sub-observer longitudes. The aim of this work was to confirm the presence of ethane ice and to determine any longitudinal trends on the surface of Pluto. We computed models of the continuum near the 2.405 lm band using Hapke theory and calculated an equivalent width of the ethane absorption feature for six evenly-spaced longitude bins and a grand average spectrum. The 2.405 lm band on Pluto was detected at the 7.5-r level from the grand average spectrum. Additionally, the band was found to vary longitudinally with the highest absorption occurring in the N 2 -rich region and the lowest absorption occurring in the visibly dark region. The longitudinal variability of 12 CO does not match that of the 2.405 lm band, suggesting a minimal contribution to the band by 13 CO. We argue for ethane production in the atmosphere and present a theory of volatile transport to explain the observed longitudinal trend.

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Search for Nonmethane Hydrocarbons on Pluto

Cited by 21 publications

References 41 publications

A search for ethane on Pluto and Triton

A search for ethane on Pluto and Triton

Laboratory Studies on the Irradiation of Methane in Interstellar, Cometary, and Solar System Ices

Evidence for longitudinal variability of ethane ice on the surface of Pluto

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