New insights on dwarf planet

A mysterious dwarf planet orbiting the Sun past Neptune is much larger than previously thought, according to an April study in The Astronomical Journal.

At 1,535 kilometres in diameter (about a third smaller than Pluto), the dwarf planet known as 2007 OR10, is the largest unnamed body in the Solar System and the third largest of the half a dozen known dwarves.

The upward estimate of 2007 OR10’S size raises the likelihood its surface is covered in volatile ices of methane, carbon monoxide and nitrogen, coatings that a smaller object would quickly shed into space.

NASA’S Kepler spacecraft, on a mission known as K2, observed the dwarf planet for 19 days in late 2014. Scientists combined that data with archival data from the infrared Herschel Space Observatory to deliver their new measurement.

“What’s really powerful is how combining K2 and Herschel data yields such a wealth of information about the object’s physical properties,” said Geert Barentsen, Kepler/k2 research scientist at NASA’S Ames Research Center in California. Naming rights for OR10 go to the object’s discoverers – astronomers Meg Schwamb, Mike Brown and David Rabinowitz who first spotted it in 2007.