NASA's New Horizons team will again attempt observations [space.com] of a stellar occultation [wikipedia.org] of 2014 MU69 [wikipedia.org], provisionally nicknamed Ultima Thule. Previous observations [soylentnews.org] made when the object passed in front of a background star suggested that it was a contact binary [soylentnews.org] and may have a small moon [soylentnews.org]:
The goal is to learn as much as possible about 2014 MU69, nicknamed Ultima Thule, which New Horizons will zoom past on Jan. 1, 2019. "This occultation will give us hints about what to expect at Ultima Thule and help us refine our flyby plans," New Horizons occultation-event leader Marc Buie, of the Southwest Research Institute in Boulder, Colorado, said in a statement.
This is not the mission team's first shadow rodeo. Last summer, scientists traveled to Argentina and South Africa for occultation observations; the Argentina crew hit the jackpot [space.com], gathering data that helped set the planned flyby distance at 2,175 miles (3,500 kilometers).
[...] Ultima Thule lies about 1 billion miles (1.6 billion km) beyond Pluto, which New Horizons famously flew by in July 2015 [space.com]. Scientists think Ultima Thule is about 20 miles (32 km) across if it's a single object; if it's two bodies, each component is probably 9 miles to 12 miles (15 to 21 km) long.
An occultation was used to determine that the dwarf planet Haumea [wikipedia.org] may have a ring system [soylentnews.org] in addition to its two known moons.