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Origin of minor planets’ rings revealed

19 September 2016 Astronomy Now

Chariklo is the largest confirmed centaur, a minor planet orbiting the Sun between Saturn and Uranus. In 2014, two rings were discovered around Chariklo. Soon after, scientists discovered that rings likely exist around another centaur, Chiron, but the origin of these rings remained a mystery — until now.

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Mystery solved: Martian moons formed by a giant impact

5 July 2016 Astronomy Now

Where did the two natural satellites of Mars, Phobos and Deimos, come from? For a long time, their shape suggested that they were captured asteroids. However, the shape and course of their orbits contradict this hypothesis. Two independent and complementary studies now provide an answer: these satellites formed from the debris of a gigantic collision between Mars and a protoplanet one-third its size.