Cometary Activity Discovered on Vacationing Centaur 2019 OE31

Abstract We have detected cometary activity on minor planet 2019 OE31 through both the Active Asteroids Citizen Science program and an independent archival search. Before 2013, 2019 OE31 was on a Centaur orbit, between the orbits of Jupiter and Neptune. Centaurs are objects in transition from the outer solar system to the inner solar system. They play a vital role in the understanding of the Kuiper Belt and comets. In 2013 October, following a close encounter with Jupiter, 2019 OE31 moved to an orbit entirely interior to that of Jupiter. This reduced orbital distance and, hence, increased temperature is likely the cause of the observed activity. Through a suite of orbital dynamics simulations, we find that 2019 OE31 will experience many more similar encounters and is statistically likely to return to a Centaur orbit, potentially within the next 80 yr, from its current “vacation.”