NASA's hypothesised that MU69, the Kuiper Belt object that is the New Horizons probe's next destination, has a moon.
To figure out what awaits New Horizons at MU69 we've peered at it with telescopes, a process that yielded a hypothesis that the object is one rock that looks a bit like a duck, or might even be two rocks smooshed together to form the anatine body.
We've also flown a 747 packing a decently-sized telescope through the shadow of MU69, using NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA).
Data from that fly-by has now been analysed and NASA's cautiously concluded that SOFIA spotted a moon.
“SOFIA detected what appeared to be a very short drop-out in the star’s light,” NASA wrote. New Horizons science team member Marc Buie, of the Southwest Research Institute, said that further analysis of that data, including correlation with MU69 orbit calculations provided by the European Space Agency’s Gaia mission, opens the possibility that the drop-out could be another object around MU69.
“A binary with a smaller moon might also help explain the shifts we see in the position of MU69 during these various occultations,” Buie said.
But the object is so distant that any observations we make between now and New Horizons' visit are rather speculative. But of course also rather worthwhile, because New Horizons' flight plan calls for it to pass within just 3,500km of the worldlet. If the rock does possess a moon, knowing about it in advance will give us a better chance of avoiding an unfortunate encounter. And any knowledge will help us to give New Horizons its best shot at doing good science once it arrives on January 1st, 2019. ®