NASA’s New Horizons spacecraft has beamed back the most detailed image yet of the Kuiper Belt object Ultima Thule (2014 MU69).
The oblique lighting of the new image reveals topographic details along the day/night boundary (terminator) near the top.
These details include numerous small pits up to about 0.4 miles (0.7 km) in diameter.
The large circular feature, about 4 miles (7 km) across, on the smaller of the two lobes, also appears to be a deep depression.
Not clear is whether these pits are impact craters or features resulting from other processes, such as ‘collapse pits’ or the ancient venting of volatile materials.
Both lobes also show many intriguing light and dark patterns of unknown origin, which may reveal clues about how this body was assembled during the formation of the Solar System 4.5 billion years ago.
One of the most striking of these is the bright ‘collar’ separating the two lobes.
“This new image is starting to reveal differences in the geologic character of the two lobes of Ultima Thule, and is presenting us with new mysteries as well,” said New Horizons principal investigator Dr. Alan Stern, a researcher at the Southwest Research Institute.
The new image was obtained with New Horizons’ Multicolor Visible Imaging Camera (MVIC) component of its Ralph instrument.
The picture was taken when Ultima Thule was 4,200 miles (6,700 km) from the spacecraft, at 12:26 a.m. EST (05:26 GMT) on January 1, 2019 — just seven minutes before closest approach.
It was stored in New Horizons’ data memory and transmitted to Earth on January 18-19.
“Over the next month there will be better color and better resolution images that we hope will help unravel the many mysteries of Ultima Thule,” Dr. Stern said.