Mon. Not. R. Astron. Soc. (in the press); preprint at http://arxiv.org/abs/1511.02230 (2015)

Saturn's rings are striking but not unique; Jupiter, Uranus and Neptune are similarly girded, as are white dwarf stars. Although we cannot observe the formation of rings within our Solar System, which may be as old as the planets, with white dwarfs this becomes possible. Indeed, Christopher Manser et al. imaged the white dwarf SDSS J1228+1040 over twelve years to understand the origin and evolution of rings.

To be precise, 'rings' are flat disks that stretch far into space. For SDSS J1228+1040, the gap between the star and the inner edge of the disk is around 700,000 km. The Doppler tomography scans taken from different angles reveal a non-circular inner edge of the disk. Moreover, the disk precesses. These observations are consistent with the disk being recently formed from a planet that got too close and was torn apart by gravity, precessing due to general relativity. This should be a short-lived phase, as radiation forces will eventually push the material inwards and symmetrize the debris disk.

One day this may happen to the Solar System.