IUE detection of bursts of HYLα emission from Saturn

A series of observations of H Lyα emission from the vicinity of Saturn are reported which were carried out between January and July 1980 using the short wavelength spectrograph of the IUE Observatory. North-south maps of the Lyα emission across the planet disk have shown pronounced spatial asymmetries in emission brightness. These asymmetries vary markedly on a time scale of days and are interpreted as bursts of Lyα emission of as much as 1 kR brightness averaged over a 6 x 10 arc s area, above a constant planetary emission level of 700 - 800 R. The Lyα emission peaks appear in fact as essentially point source features in these data. If the emitting region is smaller than the 6 x 10 arc s instrumental resolution, the surface brightness must be proportionally higher. (U.K.)