Astronomers have discovered a young, massive planet that is closer to Earth than any similar planet of similar age known to date. The object, called 2MASS 1155-7919 b, is located 330 light-years from the Sun and will allow for better study of the mechanisms of formation of gas giants, according to an article published in the journal Research Notes of the American Astronomical Society.
More than four thousand exoplanets are known today, and many of them have a mass of tens or even hundreds of times the mass of the Earth, and are probably gas giants. At the same time, scientists still do not fully know how such large celestial bodies are born. One mechanism suggests that gas giants are formed by accretion: small dust particles in the protoplanetary disk around a young star collide with each other and gradually coalesce into larger planet embryos (planetesimals), which subsequently build up mass, and the planet’s gas body is formed outside. Another mechanism allows that some very large gas giants can form like stars (only on a smaller scale) — due to the occurrence of gravitational instability in the gas-dust protoplanetary disk.
The celestial body 2MASS J1155-7919 b, discovered by researchers from the Rochester Institute of technology, is located in the constellation Chameleon and exceeds Jupiter in mass by 10 times. It is a cold and dim sub-stellar object. According to astronomers, this is probably a young planet five million years old, which is still in the formation stage. The researchers ‘ particular attention was drawn to the distance of the young giant from the parent star — the average distance between them is about 582 astronomical units, which is equivalent to 582 average distances from the Earth to the Sun.
Astronomers can’t explain how a young planet (whose status and characteristics have yet to be confirmed through additional observations)could have ended up so far from its sun. The most widely accepted nebular hypothesis by the scientific community, which says that the planets of the Solar system were formed through the coalescence of dust particles in the gas-dust disk, can not give an answer to this question.
Today, scientists know only a few such systems, including HD 106906, where the exoplanet is located 650 astronomical units from the star. Perhaps the new discovery will help researchers solve this mystery and better study the mechanisms of formation of gas giants.
Much more often, astronomers discover hot Jupiters — gas giants that rotate in very tight orbits around the star. Due to their proximity to the parent star, their surface is heated to extremely high temperatures. So, researchers last year managed to find an exoplanet with a surface temperature of 4600 Kelvins, which turned out to be hotter than most stars.