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Haifa [Israel], April 23 (ANI): New research by a team of astronomers shed new light on the formation of objects in the Kuiper Belt, asteroid-like objects at the edge of the solar system and to understand the early stages of the formation of the Solar system.
A model developed at the Technion’s Faculty of Physics, Institute of Technology, in collaboration with German scientists in Tubingen, explains the unique properties of Arrokoth, the most distant object ever photographed in the solar system.
The researchers’ findings published in the journal Nature explain the unique characteristics of ‘The Snowman’, formally known as Arrokoth. It is the farthest imaged object in the system, and the images of it were first taken last year by the New Horizons space mission.
The story begins in 2006 when the New Horizons robotic spacecraft was sent to first examine the last planet in the solar system, Pluto, which had not yet been seen up close, and study its features and terrain.
After launch, New Horizons set its path to Pluto, beginning a long journey that would last about 9 years. In order not to waste fuel and resources, most of its systems were put on “sleep” until it was close to its target, Pluto.
Meanwhile, on Earth, the international astronomical union decided to degrade Pluto from its planet-to-dwarf planet status. In short, the New Horizons robotic spacecraft was sent to investigate a planet, fell asleep and woke up to discover that Pluto was no longer considered a planet.
But this does not detract from the importance of the mission. New Horizons provided spectacular images of Pluto and its moon Charon, and provided invaluable scientific information that is still under investigation and will likely be studied for years.
These studies will provide important information to understand the formation of the solar system, and in particular the Kuiper Belt.
But there is even more to the New Horizons adventure. While Pluto is the largest object at the ends of the solar system, it is not the only one.
Beyond Neptune, in a region called the Kuiper Belt, there are numerous asteroid-like objects that range in size from a few feet to thousands of miles of large objects.
Conditions in this area are different (and in particular much colder) than your ‘brother’ asteroid belt in the inner regions of the solar system, and the Kuiper Belt objects generally consist of much icier materials.
Even before its arrival on Pluto, it was planned that the New Horizon spacecraft would still have enough resources to be able to closely observe another Kuiper Belt object if an object could be found that was not too far from the original trajectory of the spaceship.
On June 26, 2014, after an extensive survey looking for such objects, the Hubble Space Telescope identified one. Following that identification, the New Horizons research team designed the spacecraft’s trajectory to pass alongside the newly found object after completing its mission to map Pluto.
Five years later (and four after his encounter with Pluto in 2015), New Horizons passed by the object. On January 1, 2019, mankind gained its first close-up shot of a small Kuiper Belt object, thanks to the New Horizons spacecraft passing just 3,500 miles away.
Immediately after the arrival of its first images, the Kuiper Belt object (known so far as MU69 2014) was nicknamed ‘the snowman’, due to its unique appearance (see photo).
New Horizons researchers initially called it Ultima Thule (‘The Edge of the World’ in Latin), due to its remote location on the edge of the solar system). But the object eventually gained its professional name: 486958 Arrokoth, for ‘sky’ or ‘cloud’ in the Native American language Powhatan (now extinct).
The New Horizons photos and information gathered provided the scientific community with a wealth of information about the snowman: it is a 30-kilometer contact binary consisting of two lobes of different sizes interconnected with a thin neck (see photo) , which appears to be the product of two smaller Kuiper Belt objects that collided to form Arrokoth.
Although various models have been proposed to explain the formation of Arrokoth and its peculiar properties, they encountered great challenges and were unable to explain the important characteristics of the snowman, in particular its slow speed of rotation around itself and its large angle of inclination. .
In their Nature article, the Technion researchers present new analytical calculations and detailed simulations that explain the formation and characteristics of Arrokoth.
The research was led by Ph.D. Evgeni Grishin, postdoctoral fellow Dr. Uri Malamud and his supervisor, Professor Hagai Perets, in collaboration with the German research group in Tübingen.
“A simple high-speed collision between two random objects in the Kuiper Belt would tear them apart, as they are likely to be made primarily of soft ice. If the two bodies orbit each other in a circular orbit (similar to the Moon orbiting the Earth), and then slowly spiral to more smoothly approach and make contact, Arrokoth’s rotational speed would have been extremely high, while the measured speed was actually quite low relative to such expectations, “Grishin said.
“Arrokoth’s full rotation, ‘one day’, lasts 15.92 hours. Furthermore, its tilt angle (relative to the plane of its orbit around the Sun) is very large – 98 degrees – so it is almost on the relative side to its orbit, a peculiar characteristic in itself. ” Grishin added.
“According to our model, these two bodies rotate around each other, but because they rotate together around the Sun, they basically constitute a triple system,” he continued.
“The dynamics of such triple systems is complex and notoriously known as the three-body problem. The dynamics of gravitational triple systems are known to be very chaotic. In our study, we demonstrated that the system did not move in a simple and orderly fashion. but he also didn’t behave in a totally chaotic way, “he said.
“It evolved from having a broad and relatively circular orbit, to a highly eccentric elliptical orbit through slow (secular) evolution, much slower compared to the Arrokoth orbital period around the Sun.” Professor Perets said.
“We could show that such trajectories eventually lead to a collision, which on the one hand will be slow, and will not crush objects, but on the other hand, will produce a slowly rotating, highly tilted object consistent with the properties of Arrokoth,” Perets added. .
“Our detailed simulations confirmed this image and produced models very similar to the appearance, rotation, and tilt of the Arrokoth Snowman,” said Dr. Malamud.
The researchers also studied how robust and likely such processes are, and found that they are potentially quite common with up to 20% of all wide Kuiper Belt binaries and potentially evolve similarly.
Until now, the researchers said, it was not possible to explain Arrokoth’s unique characteristics. It is a counterintuitive result, but the probability of collision in such configurations actually increases as the initial binary is more widely separated (but still linked) and the initial tilt angle is closer to 90 degrees.
“Our model explains both the high probability of collision and the unique data from today’s unified system, and indeed predict that there are many more objects in the Kuiper Belt,” said Mr. Grishin.
“In fact, even the Pluto and Charon system could have been formed through a similar process, and they appear to play an important role in the evolution of binary and lunar systems in the solar system,” added Grishin. (AND ME)
