(Updated: 08:07 14.09.2018)
MOSCOW, September 14 (Itar-Tass) – RIA Novosti, Tatjana Pichugina. The star TRAPPIST-1 found seven planets, very similar to the earth. All are covered with a dense atmosphere and have enormous reserves of liquid water. Despite the hard radiation of the red dwarf, scientists regard these celestial bodies as the most promising for seeking life.
The closest family of exoplanets
The TRAPPIST-1 star in the constellation of Aquarius is only 39 light-years away. It is a red dwarf, very small and cold compared to the sun, moderately active. In 2016 astronomers discovered three planets that revolved around it. Their disks on the background of the stars were repaired by orbital and terrestrial telescopes.
A year later, four planets were discovered in the system. They are all as big as the earth, but because of the small mass of the star (eight percent of the mass of the sun) they are super compact. The diameter of the TRAPPIST-1 planetary system, in fact called in honor of the "saw" its Belgian telescope in Chile – only 0.06 the distance from the sun to the earth (one astronomical unit).
In the TRAPPIST-1 system, the most well-known earth-like, to date, inhabited planets. The periods of their revolution around the star are multiples of each other, which allows us to speak about the longest chain of resonances – the planets approach each other periodically.
Russian scientists – Artem Burdanov from Ural Federal University and Alexei Chushev, graduate student from the University of Leicester (Great Britain) took part in the discovery of this amazing planetary system.
Planetary system TRAPPIST-1 in comparison with the solar system
History of the red dwarf
TRAPPIST-1 – very faded star, making it difficult to study. Similar red dwarfs are common in the universe, they are responsible for most of the star matter of the Milky Way. It is assumed that these are young stars. But the analysis of the data showed: TRAPPIST-1 is an exception. Her age is estimated at 7.6 billion years and even more.
Plasma emissions of hair are rare. The structure of the photosphere is unknown, but astronomers suggest that there may be gigantic cold spots and small, very hot flares with a temperature of more than four thousand Kelvins.
Because of the proximity of the light, the planets are under strong ultraviolet and X-rays, able to literally sterilize the surface and destroy the atmosphere. Such intense radiation can not withstand any of the known microorganisms on earth, including the most radiation-resistant bacterium Deinococcus radiodurans.
Only a dense atmosphere with an ozone layer offers a chance for near-earth conditions. In any case, scientists are preparing for the search for the atmosphere of planets, and in that – biomarkers that increase the probability of the birth of life, in the first place – ozone.
So the artist proposed conditions on the planets of the TRAPPIST-1 system
The atmosphere of the planets is rich in hydrogen, but can be blown out by the rigid radiation of the star. Although all celestial bodies consist predominantly of stone, they are almost a third of the water. Ice is, gas or oceans – is unknown. By comparison, the world ocean is only 0.02 percent of the Earth's mass.
Scientists believe that the abundance of water speaks about the remote origin of the planets and the subsequent migration of them closer to the star. It is not excluded that they gradually changed their order. According to another hypothesis, comets have brought water to the planets, which they bombed intensively in the initial phase of the formation of the system.
Closest to the star TRAPPIST-1b, c and d are too hot to hold liquid water. The seventh planet, TRAPPIST-1 hour, is too cold. Liquid water on the surface is only possible because of the warming of the interior by the tidal effect or by the well-conserved, hydrogen-rich primary atmosphere.
The most interesting for astronomers are three medium-sized planets. TRAPPIST-1e is completely made of stone, but there are insufficient volatile components and water. In comparison with the neighbors, this is a dry planet, reminiscent of the great Mercury, which causes the atmosphere and part of the mantle to be lost because of the impact of a celestial body with much larger dimensions than itself.
Planet f is probably surrounded by a country-like atmosphere, under which the oceans are hidden. The close proximity of neighbors can, however, make a cruel joke: the tidal effect that is created during the approach of the planets warms up the interior, and instead of water, vast oceans of magma rage to the surface.
In the atmosphere there is carbon dioxide, which forms ice caps on the night side. According to one scenario, some planets experience a strong greenhouse effect, reducing the chance of finding life there.
In the near future, scientists hope to discover the eighth planet of TRAPPIST-1 and already actively predict its orbit. On the James Webb Space Telescope hopes are established, its launch is planned for 2021. Until that time, virtually all information about the composition and origin of the planets will remain very hypothetical, and many scenarios of what goes on in the atmosphere and happening on the surface may prove to be incorrect.
So the artist imagined the planet TRAPPIST-1d and his two "cousins"