Ceres . But between 2002 and 2004, Quaoar was the largest known Trans-Neptunian object other than Pluto and Pluto's moon Charon .) The diameter of Sedna is roughly three-quarters that of Pluto, but notably larger than Quaoar. Date 15 March 2004 ( 2004-03-15 ) Source http://photojournal.jpl.nasa.gov/catalog/PIA05567 http://ipac.jpl.nasa.gov/media_images/ssc2004-05c_medium.jpg Author NASA/JPL-Caltech Permission (