Planet with rings 200 times bigger than Saturn found. General Knowledge January 2015.

Scientists have discovered a planet with a ring around it that is 200 times larger than that of Saturn.
Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester discovered the ring system 420 light years away. The system was spotted circling brown dwarf J1407b — a planet orbiting star J1407 — because of the unusual, unsteady light observed during a 52 day eclipse.

The ring system likely contains roughly an Earth’s worth of mass in light-obscuring dust particles.

The light curve tells astronomers that the diameter of the ring system is nearly 120 million km, more than 200 times as large as the rings of Saturn. Astronomers estimate that the ringed companion J1407b has an orbital period roughly a decade in length. The mass of J1407b has been difficult to constrain, but it is most likely in the range of about 10 to 40 Jupiter masses. The new analysis led by Leiden’s Matthew Kenworthy shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter.