NASA’s New Horizons probe has returned the sharpest images of Ultima Thule to date, taken during the spacecraft’s historic flyby of the Kuiper Belt object on January 1, 2019.
This composite picture combines nine individual images taken with New Horizons’ Long Range Reconnaissance Imager (LORRI), each with an exposure time of 0.025 seconds, just 6 ½ minutes before the spacecraft’s closest approach to Ultima Thule. The image was taken at 12:26 a.m. EST (5:26 a.m. GMT) on January 1, 2019, when the spacecraft was 4,109 miles (6,628 km) from Ultima Thule and 4.1 billion miles (6.6 billion km) from Earth. The angle between the spacecraft, Ultima Thule and the Sun — known as the ‘phase angle’ – was 33 degrees. Image credit: NASA / Johns Hopkins Applied Physics Laboratory / Southwest Research Institute / National Optical Astronomy Observatory.
“Getting these images required us to know precisely where both tiny Ultima and New Horizons were — moment by moment — as they passed one another at over 32,000 mph (51,500 km per hour) in the dim light of the Kuiper Belt, a billion miles beyond Pluto,” said New Horizons principal investigator Dr. Alan Stern, a researcher at the Southwest Research Institute.
“This was a much tougher observation than anything we had attempted in our 2015 Pluto flyby.”
The higher resolution brings out many surface features that weren’t readily apparent in earlier images of Ultima Thule.
Among them are several bright, enigmatic, roughly circular patches of terrain.
In addition, many small, dark pits near the terminator — the boundary between the sunlit and dark sides of the body — are better resolved.
“Whether these features are craters produced by impactors, sublimation pits, collapse pits, or something entirely different, is being debated in our science team,” said New Horizons deputy project scientist Dr. John Spencer, also from the Southwest Research Institute.
“These observations were risky, because there was a real chance we’d only get part or even none of Ultima Thule in the camera’s narrow field of view,” Dr. Stern said.
“But the science, operations and navigation teams nailed it, and the result is a field day for our science team!”
“Some of the details we now see on Ultima Thule’s surface are unlike any object ever explored before.”
