Evidence of a Polar Cyclone on Uranus From VLA Observations

We present observations of Uranus in northern spring with the Very Large Array from 0.7 to 5 cm. These reveal details thermal emission Uranus' north pole at 10s bars, including a dark collar near 80°N and bright spot polar center. The central resembles on Saturn Neptune shallower pressures. constrain variations temperature NH3/H2S abundances which could explain these features. find that brightness can be recreated through K gradients and/or 10× depletion NH3 or H2S vapor between 10 20 both consistent presence cyclonic vortex. contrast may have increased since 2015, would suggest seasonal evolution circulation depth.