Astronomers using a telescope «Hubble»discovered that one of the asteroid systems in the Kuiper belt may not be a double, but a triple.
If this discovery is confirmed, it will be only the second example of such a complex system in the distant Kuiper belt, which is hidden behind the orbit of the planet Neptune. It may also change the way scientists think about the formation of systems asteroids in the Kuiper belt.
The system, which has already been named 148780 Altjira, allows scientists to improve their own models of how three gravitationally interconnected objects move in outer space.
The so-called «The problem of three bodies»
«The universe is filled with many three-body systems, including the stars closest to Earth — the Alpha Centauri star system, and we find that the Kuiper belt may not be an exception», — emphasizes a graduate of the Faculty of Physics and Astronomy at Brigham Young University, head of a group of astronomers Maya Nelsen
The first icy space object in the Kuiper belt, known as 1992 QB, was discovered by astronomers Dave Jewitt and Jane Lu in 1992. Since then, another 3 thousand objects have been added to the catalog
Scientists estimate that the Kuiper belt, which is shaped like an ice bagel and is located at a distance of 4.5 billion kilometers from the Sun, may contain several hundred thousand more objects with a diameter of more than 16 km.
It is believed that the Kuiper belt extends up to 7.4 billion kilometers from the Sun, which is about 50 times the distance between the Earth and our parent star.
The Altjira triple asteroid system is located in the center of the Kuiper belt, 6 billion km from the Sun.
The first images obtained with the telescope «Hubble», indicated that the Altjira 148780 system consists of two objects located at a distance of 7.6 thousand km from each other
However, repeated observations revealed that one of the objects actually consists of two asteroids.
These asteroids are so close to each other that they cannot be separately distinguished from such a great distance.
«For objects this small and this distant, the distance between the two inner members of the system is a fraction of a pixel on the Hubble camera, so to detect that it is a triple, you have to use methods not related to imaging», — explains Maya Nelsen.
It took astronomers 17 years and data from «Hubble» and the Keck Observatory at Hawaii to observe changes in the Altjira system’s orbit and draw final conclusions
The information obtained was added to various modeling scenarios, the most likely of which is the presence of a system of three gravitationally interconnected asteroids.
«Other possibilities are that the inner object is a contact binary system, where two separate bodies get so close that they collide with each other, or something actually surprisingly flat, like a pancake», — suggests Maya Nelsen
Astronomers’ observations with the help of «Hubble» by the Altjira system confirm the theory of the origin of the Kuiper belt, which predicts the direct gravitational collapse of matter that had the shape of a disk and surrounded the young Sun 4.5 billion years ago
This collapse is similar to the process of star formation, but on a much smaller scale. The formation of stars from dense regions of dust and gas can also lead to the emergence of double and triple systems.
An alternative theory of the Kuiper Belt, which views these icy asteroids as the result of collisions of large bodies, would not have led to the formation of a triple system, as presented in the Altjira system.
The upcoming observations of Altjira by the space telescope will be especially interesting «James Webb» on its third anniversary.
«Altjira has entered the eclipse season, when the outer body passes in front of the central body It will continue for the next 10 years, which will give scientists a great opportunity to learn more about it,» adds Maya Nelsen
The study was published in the journal The Planetary Science Journal
Source: space.com