Atomic hydrogen corona of Uranus

We have analyzed Voyager 2 ultraviolet spectrometer observations of the H Lyman α emission from the atomic hydrogen corona of Uranus. The resulting estimated hydrogen density distribution has a radial profile ~1/r². This distribution implies a weakly bound or escaping population of hot (>2 eV) hydrogen not thermalized with the 0.07 eV thermosphere/exosphere. The hot H density is enhanced on the sunward side of Uranus, with the maximum weakly associated with the dayside magnetic pole. The source of this hot hydrogen is presumably near the position we have found for the density maximum. Therefore we suggest that this source of hot H atoms may be associated either with electroglow or else with the dayside aurora.