Published online by Cambridge University Press: 12 April 2016
We present an updated study of Uranus interior models using current information about the planet’s gravity field and rotation rate. The most plausible model, both from the point of view of recent data and cosmogony, has a central core of iron and magnesium silicates, an outer envelope of liquid water, methane, and ammonia, and a deep “atmosphere” of almost four earth masses of hydrogen, helium, and methane. The “atmosphere” contains a gravit at ionally nonnegligible amount of methane — about 40% by mass. All plausible models are most consistent with a rotation period of ~15 to 16 hours.