Animation Comparing Rotation Rates of Jupiter, Saturn, and Brown Dwarf 2MASS J0348-6022

This animation compares the rotation rates of Jupiter and Saturn to that of the fastest-spinning brown dwarf yet discovered (named 2MASS J0348-6022). Brown dwarfs are more massive than any of the giant planets in our solar system but less massive than stars. This brown dwarf is actually about the same size as Jupiter, but it has about 43 times more mass and spins almost 10 times faster. This rapid rotation causes the brown dwarf to “flatten,” or become wider around its equator. Jupiter and Saturn are flattened as well. The brown dwarf’s faster rotation is balanced by its larger mass, giving it a shape similar to that of the slower-rotating Jupiter and Saturn. The shapes of these three objects are compared to perfect circles (drawn in white) in this animation.