Search for spatial variation in the jovian 15N/ 14N ratio from Cassini/CIRS observations - Archive ouverte HAL
Article Dans Une Revue Icarus Année : 2004

Search for spatial variation in the jovian 15N/ 14N ratio from Cassini/CIRS observations

Résumé

We have used the spectra obtained by the Composite Infrared Spectrometer (CIRS) onboard the Cassini spacecraft to search for latitudinal variation in the 15N/ 14N ratio on Jupiter. We found no variations statistically significant given the observational and model uncertainties. The absence of latitudinal variations demonstrates that 15NH 3 is not fractionated in Jupiter's atmosphere, and that the measured 15N/ 14N represents Jupiter's global value. Our mean value for the global jovian 15N/ 14N ratio of (2.22±0.52)×10 -3 agrees with previous measurements made by Fouchet et al. (2000, Icarus 143, 223-243) and Owen et al. (2001, Astrophys. J. 553, L77-L79). We argue that the jovian isotopic 15N/ 14N ratio must represent the solar nitrogen isotopic composition. The solar 15N/ 14N ratio hence significantly differs from the terrestrial value: ( 15N/ 14N) =3.68×10 -3. This supports the proposition that terrestrial nitrogen originates from a nitrogen reservoir isolated from the main nitrogen reservoir in the proto-solar nebula. The origin and carrier of this isolated reservoir are still unknown.

Dates et versions

hal-03732617 , version 1 (21-07-2022)

Identifiants

Citer

Thierry Fouchet, Patrick G. J. Irwin, Paul David Parrish, Simon B. Calcutt, Frederic W. Taylor, et al.. Search for spatial variation in the jovian 15N/ 14N ratio from Cassini/CIRS observations. Icarus, 2004, 172, pp.50-58. ⟨10.1016/j.icarus.2003.11.011⟩. ⟨hal-03732617⟩
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