Ultima Thule first seemed to be an amalgam of two vaguely spherical objects, but the new image is telling us that appearances can be deceiving, especially at 4.1 billion miles away.
"Most of the so called "Ultima" is like a big pancake, but smaller, "Tula", reminiscent of a flattened walnut" - the researchers note.
"We've never seen anything like this orbiting the Sun", NASA said in a statement. Ultima Thule may very well be one of them-which means every bit of new information on this mysterious object could be crucial. This has given scientists a way to get a better sense of its shape.
When the first images of the spacecraft arrived, scientists thought Ultima Thule looked like a bowling pin, with the name of "snowman" given to it. New Horizons' camera was forced to use a longer exposure time to capture the photos, blurring the images.
The new images were taken at approximately 12:42 a.m. EST (05:42 GMT) Jan. 1, 2019, approximately 10 minutes after closest approach from a position 5,494 miles (8,862 kilometers) past Ultima Thule and an incredible 4.1 billion miles (6.6 billion kilometers) from Earth.
Watching which background stars "blinked out" as the object passed in front of them allowed scientists to outline the shape of both lobes, which was then compared to a model assembled from analysing pre-flyby images and ground-based telescope observations.
Project scientist Hal Weaver of Johns Hopkins University, home to New Horizons flight control center, said the finding should spark new theories on how such primitive objects formed early in the solar system. The dashed blue lines represent uncertainty, indicating that Ultima Thule could be either flatter than, or not as flat as, depicted in this figure.
New Horizons - the legendary spacecraft that captured these images of MU69 - shot the latest sequence of pictures on January 1, 2019, as the spacecraft departed MU69 at 31,000 miles per hour and hurtled deeper into the black abyss of space, toward still-unknown destinations. Preliminary measurements of this Kuiper Belt object suggest it is approximately 20 miles long by 10 miles wide (32 kilometers by 16 kilometers).
Rather than being two relatively spherical bodies in contact with each other, Ultima Thule in this new analysis is determined to be much more squashed.
Stars can be seen "blinking out" in the background of an animation created from several images stitched together as New Horizons flew by. On that day, it had its close-up flyby of the Edgeworth-Kuiper Belt object known as Ultima Thule, a chunk of space debris that had previously caught the eye of astronomers of Earth. The two likely joined as early as 99 percent of the way back to the formation of the Solar System, colliding no faster than two cars in a fender bender.