Astronomers Discover a 1.3-km Object on the Edge of Our Solar System
Astronomers have discovered a celestial body with a radius of 1.3 kilometres at the edge of the Solar system. The existence of celestial bodies of several kilometers in size has been theorized by astronomers as far back as 70 years ago. These bodies are crucial to our understanding of planet formation.
The Kuiper belt is a circumstellar disk located outside the orbit of Neptune, a ring-shaped accumulation of matter that includes gas, dust, planetesimals, asteroids and collision fragments. With Pluto as its most famous belt object, the Kuiper belt is believed to consist of object that are remnants of material from when the Solar system was formed.
The small bodies of the inner part of the Solar system, such as the asteroids of the Main Belt Asteroid, experience changes over time due to solar radiation, collisions and gravity of the planets, while in the Kuiper belt, objects have remained unchanged since the formation of the Solar system. Astronomers study them to gain insight about the processes of planet formation.
The Kuiper belt objects with a radius of several kilometers are too far, too small in size and too bright to be observed directly even with the most powerful modern telescopes, such as the Subaru telescope. However, in a new study, a group of researchers led by Ko Arimatsu from the National Astronomical Observatory of Japan used a method based on an eclipse of a star by an object of the Kuiper belt during the passage of an object in front of a star. The team of the sky review of Organized Autotelescopes for Serendipitous Event Survey has placed two small, 28-cm telescopes on the roof of the school in Okinawa Prefecture and observed approximately 2,000 stars for 60 hours.
After analysing the collected data, the team confirmed an eclipse of one of the stars by a Kuiper belt object in front with a radius of 1.3 kilometers.
The results suggest that kilometre-sized planetesimals in the Kuiper belt are more numerous than previously thought. And this, in turn, speaks in favor of the theory that planetesimals first grow to objects several kilometers in size, and then rapidly merge with larger bodies, such as planets.
As of today, scientists believe after a star is born, it is surrounded by a disk of residual dust and gas circling in its orbit. Electrostatic forces bind particles in this protoplanetary disk with each other and form a clump. As the clump grows in size, its gravitational force also increases, which collects more and more particles, adding to the increase in size, and in the end, becomes a planet.
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