2002_WC19
(119979) 2002 WC19 (provisional designation 2002 WC19) is a twotino, that is, a planetoid in a 1:2 orbital resonance with Neptune. It was discovered on November 16, 2002 at the Palomar Observatory. If its derived diameter is correct it would have a higher density than Pluto, which is unusual as it appears to be much smaller than the expected size at which a Kuiper belt object usually becomes solid.
Knowing how many twotinos there are may reveal whether Neptune took roughly 1 million or 10 million years to migrate about 7 AU from its birth location.[8]