Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment

Donald E. Jennings, C. A. Nixon, P. N. Romani, G. L. Bjoraker, P. V. Sada, A. W. Lunsford, R. J. Boyle, B. E. Hesman, G. H. McCabe

Resultado de la investigación

Resumen

As the main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS1 and from the ground2 and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes. 1Nixon et al., Icarus 195, 778 (2008). 2Jennings et al., Journal of Physical Chemistry A, in press (2009).
Idioma originalEnglish
PublicaciónAmerican Astronomical Society, DPS meeting #50
Volumen41
EstadoPublished - 1 sep 2009
Publicado de forma externa

Huella dactilar

Titan
ethane
methane
carbon
planet
isotope
kinetics
atmosphere

Citar esto

Jennings, D. E., Nixon, C. A., Romani, P. N., Bjoraker, G. L., Sada, P. V., Lunsford, A. W., ... McCabe, G. H. (2009). Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment. American Astronomical Society, DPS meeting #50, 41.
Jennings, Donald E. ; Nixon, C. A. ; Romani, P. N. ; Bjoraker, G. L. ; Sada, P. V. ; Lunsford, A. W. ; Boyle, R. J. ; Hesman, B. E. ; McCabe, G. H. / Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment. En: American Astronomical Society, DPS meeting #50. 2009 ; Vol. 41.
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abstract = "As the main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS1 and from the ground2 and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes. 1Nixon et al., Icarus 195, 778 (2008). 2Jennings et al., Journal of Physical Chemistry A, in press (2009).",
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Jennings, DE, Nixon, CA, Romani, PN, Bjoraker, GL, Sada, PV, Lunsford, AW, Boyle, RJ, Hesman, BE & McCabe, GH 2009, 'Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment', American Astronomical Society, DPS meeting #50, vol. 41.

Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment. / Jennings, Donald E.; Nixon, C. A.; Romani, P. N.; Bjoraker, G. L.; Sada, P. V.; Lunsford, A. W.; Boyle, R. J.; Hesman, B. E.; McCabe, G. H.

En: American Astronomical Society, DPS meeting #50, Vol. 41, 01.09.2009.

Resultado de la investigación

TY - JOUR

T1 - Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment

AU - Jennings, Donald E.

AU - Nixon, C. A.

AU - Romani, P. N.

AU - Bjoraker, G. L.

AU - Sada, P. V.

AU - Lunsford, A. W.

AU - Boyle, R. J.

AU - Hesman, B. E.

AU - McCabe, G. H.

PY - 2009/9/1

Y1 - 2009/9/1

N2 - As the main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS1 and from the ground2 and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes. 1Nixon et al., Icarus 195, 778 (2008). 2Jennings et al., Journal of Physical Chemistry A, in press (2009).

AB - As the main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS1 and from the ground2 and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes. 1Nixon et al., Icarus 195, 778 (2008). 2Jennings et al., Journal of Physical Chemistry A, in press (2009).

M3 - Article

VL - 41

JO - American Astronomical Society, DPS meeting #50

JF - American Astronomical Society, DPS meeting #50

ER -

Jennings DE, Nixon CA, Romani PN, Bjoraker GL, Sada PV, Lunsford AW y otros. Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment. American Astronomical Society, DPS meeting #50. 2009 sep 1;41.