Sedna

"Orbiting at almost three times the distance of Neptune's orbit from the Sun, Sedna is quite large for its orbital neighborhood and easily recognizable as one of the reddest worlds in the outer Solar System.With an orbit taking 11,400 years to complete, many scientists believe that Sedna was actually captured from a passing solar system by our Sun's gravity, or even that its orbit may be evidence for a large planet beyond the orbit of Neptune."