Structure and evolution of Uranus and Neptune

Journal Article · Thu Jan 10 04:00:00 EST 1980 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB085iB01p00225· OSTI ID:5449912

Hubbard, W B; MacFarlane, J J

We present three-layer interior models of Uranus and Neptune with central rocky cores, mantles of water, methane, and ammonia (the 'ices'), and outer envelopes primarily composed of hydrogen and helium. The models incorporate a new H/sub 2/O equation of state based on experimental data which is considerably 'softer' than previous H/sub 2/O equations of state. Corrections for interior temperature approx.5000 /sup 0/K are included in the models, and the thermal evolution of both planets is investigated using recent heat flow measurements. We find that evolutionary considerations are consistent with gravitational field data in supporting models with approximately solar abundances of 'ice' and 'rock.' Models with very low abundances of water, methane, and ammonia can be excluded. Evolutionary considerations indicate that initial temperatures and luminosities for Uranus and Neptune were not substantially higher than the present value. Both planets apparently have relatively small (approx.1--2 earth masses) hydrogen-helium envelopes, with Neptune's envelope smaller than Uranus'. A monotonic trend is evident among the Jovian planets: all have central rock-ice cores of approx.15 earth masses, but with hydrogen-helium envelopes which decrease in mass from Jupiter to Saturn to Uranus to Neptune.

• Research Organization: Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721
• OSTI ID: 5449912
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 85:B1; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKANES
AMMONIA
CRYOGENIC FLUIDS
ELEMENTS
EQUATIONS
EQUATIONS OF STATE
FLUIDS
GEOLOGIC HISTORY
GEOLOGIC MODELS
HEAT FLOW
HELIUM
HYDRIDES
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
ICE
METHANE
NEPTUNE PLANET
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLANETARY EVOLUTION
PLANETS
RARE GASES
SOLAR SYSTEM EVOLUTION
URANUS PLANET
WATER