Internal structure of Uranus

An updated study is presented 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 gravitationally nonnegligible amount of methane - about 40% by mass. All plausible models are most consistent with a rotation period of 15 to 16 hours.