Theoretical predictions of deuterium abundances in the Jovian planets

W. B. Hubbard, J. J. MacFarlane

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Using current concepts for the origin of the Jovian planets and current constraints on their interior structure, we argue that the presence of large amounts of "ice" (H2O, CH4, and NH3) in Uranus and Neptune indicates temperatures low enough to condense these species at the time Uranus and Neptune formed. Yet such low temperatures imply orders-of-magnetude fractionation effects for deuterium into the "ice" component if isotopic equilibration can occur. Our models thus imply that Uranus and Neptune should have a D/H ratio at least four times primordial, contrary to observation for Uranus. We find that the Jovian and Saturnian D/H should be close to primordial regardless of formation scenario. The Uranus anomaly could indicate that there was a strong initial radial gradient in D/H in the primordial solar nebula, or that Uranus is so inactive that no significant mixing of its interior has occurred over the age of the solar system. Observation of Neptune's atmospheric D/H may help to resolve the problem.

Original languageEnglish (US)
Pages (from-to)676-682
Number of pages7
JournalIcarus
Volume44
Issue number3
DOIs
StatePublished - Dec 1980

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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