UPDATE: 2014 MU69 is now officially named Arrokoth
Three days after its historic flyby, New Horizons continues to transmit data at about 500 bits per second from the depth of the Kuiper Belt, the area of the Solar System beyond the orbit of Neptune and home to Ultima Thule. The team has provided an update in a press conference.
We now know that Ultima Thule is a contact binary, the second visited by a probe after the European Space Agency’s Rosetta visit to comet 67P/Churyumov-Gerasimenko. The two original objects – Ultima (the bigger one) and Thule (the smaller one) – came together in a slow impact that formed its now iconic neck.
The formation model developed by the team suggests the two objects significantly slowed down over time until they managed to gently smush into each other. To do so, something must have taken the momentum away. The researchers suggest that one or a series of moons could be responsible for this. However, no moon larger than 1.6 kilometers (1 mile) or even a ring system have been found yet.
Ultima Thule is also lacking an atmosphere. This is not a surprise for such a small world, although researchers confirmed that the solar wind does impact the surface, which might have important consequences.
Another crucial update might not seem that exciting at first, but it's good news. The team has confirmed that Ultima Thule’s color is typical of other Kuiper Belt Objects (KBOs). Now, one usually gets excited about exceptional things, but given the fact this will probably be the only KBO studied in detail for decades to come, it is very important that it is representative.
The colors of Ultima and Thule are also the same on average. Again as expected for two objects formed together in the Kuiper Belt. The team has also released a new image taken about 38 minutes after the snowman picture released yesterday. They combined them in a stereo view (if you have the red and green glasses) and a little animation.
The press conference also gave a shoutout to the artists helping the team: James Tuttle Keane, Leila Gabasova, and Mallory Kinczyk. Starting tomorrow, the slow-but-steady data transmission will pause for about a week. New Horizons will be obscured by the Sun as seen from Earth. It will resume on January 10 and will continue until September 2020.
"The first exploration of a small Kuiper Belt object and the most distant exploration of any world in history is now history, but almost all of the data analysis lies in the future," New Horizon’s Principal Investigator Alan Stern, from the Southwest Research Institute, said in a statement. "Those of us on the science team can't wait to begin to start digging into that treasure trove."