Discovery of a Dark Auroral Oval on Saturn


  • The ultraviolet image was obtained by the NASA/ESA Hubble Space Telescope with the European Faint Object Camera (FOC) on June 1992. It represents the sunlight reflected by the planet in the near UV (220 nm).



  • The image reveals a dark oval encircling the north magnetic pole of Saturn. This auroral oval is the first ever observed for Saturn, and its darkness is unique in the solar system (L. Ben-Jaffel, V. Leers, B. Sandel, Science, Vol. 269, p. 951, August 18, 1995). The structure represents an excess of absorption of the sunlight at 220 nm by atmospheric particles that are the product of the auroral activity itself. The large tilt of the northern pole of Saturn at the time of observation, and the almost perfect symmetry of the planet's magnetic field, made this observation unique as even the far side of the dark oval across the pole is visible!
  • Credit:

    L. Ben Jaffel, Institut d'Astrophysique de Paris-CNRS, France, B. Sandel (Univ. of Arizona), NASA/ESA, and Science (magazine).

    About the Image

    NASA press release
    NASA caption
    Release date:10 October 1995, 05:00
    Size:708 x 643 px

    About the Object

    Type:• Solar System : Planet : Type : Gas Giant
    • Solar System : Planet : Ring

    Image Formats

    Large JPEG
    128.0 KB
    Screensize JPEG
    208.1 KB

    Colours & filters

    220 nm Hubble Space Telescope

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