Astronomers have used observations from the Kepler space telescope and the Herschel Space Observatory to determine that the trans-Neptunian object "2007 OR10" is bigger than previously thought, and now ranks third in the solar system's dwarf planet size league table, behind Pluto and Eris.
The distant body was first spied back in 2007, as its provisional name indicates, by skygazers Mike Brown, David Rabinowitz and Meg Schwamb during "a survey to search for distant solar system bodies using the Samuel Oschin Telescope at Palomar Observatory near San Diego, California", as NASA puts it.