IUE views Europa: Temporal variations in the UV

Observations taken with the International Ultraviolet Explorer (IUE) show the first detection of temporal changes in the UV spectral reflectance of the Jovian quadrant of Europa's leading side between 15°–75° longitude over a time scale considered extraordinarily short for a large planetary object (commensurate with possible resurfacing events). The central trailing side region displays a 0.28 µm SO2 absorption that has remained constant in relative depth over the past decade to within the instrument detection limits. A new 0.33 µm absorption feature is seen on the leading side.