The mysterious trans-Neptune asteroid continues to amaze scientists with its nature. New data show that we have a very unique space object. How was the Ultima Thule formed?
Unusual asteroid
Researchers were lucky to see this object close due to the spacecraft New Horizons, which flew past January 1, 2019. The distance between the ship and the celestial body was only 3,500 km. And this is really a great success, because Ultima Thule lives at a distance of 6.5 billion km!
This is a classic Kuiper belt resident who has to spend more than 293 years on one revolution around the Sun. The size can reach 30-45 km. The team of New Horizons in 2015 chose this object as a target for the span, but reached only in 2019.
More on the first photos of Ultima Thule (2014 MU69) surprised with its unusual shape. With further rapprochement, scientists put forward various explanations. At one point, it seemed that we had a cosmic snowman, created by two merged spheres. But further analysis showed that these are not spheres, but petals (large — Ultima and small — Thule). Moreover, the shape of the petals is different. One resembles a massive pancake, and the second - a flattened walnut.
Strange form
The form really raises a lot of questions. This asteroid is now called Frankenstein, because, like the monster of a scientist, it is also created from various parts. The researchers intently peer into every detail, since the asteroid has managed to survive well and reflects the period of the formation of the planets (the era of planetesimals).
It is believed that two large “petals” attracted, long rotated around each other, until they underwent the process of smooth merging (without destruction) at a speed of 3 m / s. The point of fusion is called the “neck” (a remarkable bend between the petals).
Surface Features
Ultima Thule Surface Features
But this is not the end. A detailed review of the surface noticed a huge number of bright spots, depressions, hills, grooves and craters. The latter resemble the events of impact craters, but there is a variant that the origin may be different.
Some scientists suspect that at Ultima Thule there is a process of sublimation, where the ice is transformed directly into a gas without a liquid stage. Then on the place of ice deposits there are dredging. Or the whole point is that the material somehow flows into subsurface cracks. The largest depression seen covers a width of 8 km. Only the surface color doesn’t cause any problems, due to which Ultima Thule resembles the standard Kuiper belt family of celestial bodies. However, it seems that its surface layer is divided into separate geological territories.
Postscript
Scientists are convinced that these are not the last surprises from a strange trans-Neptune asteroid. While the ship New Horizons continues to move deep into the Kuiper belt (now removed by 6.6 billion km), it will transmit all the collected information about the object until 2020, simultaneously covering other celestial bodies.
