The Hubble Orbital Observatory helped planetary scientists to prove that at least three planets in the TRAPPIST-1 system have a "normal" atmosphere and significant water reserves, making them prime candidates for a refuge for extraterrestrial life, according to an article published in the journal Nature Astronomy …
“After we discovered this amazing family of planets, our team was looking forward to learning something new about TRAPPIST-1. A year has passed, and now we can tell about what we managed to discover. Gradually, these seven planets become the most well-studied worlds outside the solar system,”said Amaury Triaud of the Astronomical Institute in Cambridge, UK.
In May 2015, astronomers from MIT announced the discovery of an extremely unusual star system in the immediate environment of the Earth - TRAPPIST-1, located only 40 light years away from us in the direction of the constellation Aquarius. All three planets orbiting this red dwarf are located inside the so-called zone of life, where water can exist in liquid form, and, presumably, have a mass comparable to that of Earth.
Later, Trio and his colleagues studied the spectrum of rays of the star TRAPPIST-1, trying to determine the composition of the atmosphere of its planets, and suddenly discovered that in fact there are not three, but seven, with six located within the zone of life. Calculations show that life, in principle, can exist on the surface of two planets - TRAPPIST-1f and TRAPPIST-1g, which are most similar to the Earth in their composition and properties.
One of the main mysteries of the "seven sisters", according to the planetary scientist, was whether there is water on their surface and whether it can exist there for a sufficient time for life to arise. Trio and his colleagues announced the discovery of traces of water in the TRAPPIST-1 system back in September last year, but then it was not clear whether this water was present on the planets themselves or in space between them.
To answer this question, scientists conducted an additional series of observations of the four most interesting planets of the system - d, e, f, g, using the instruments of the Hubble Space Telescope.
New data on how strongly these planets obstruct the light of a red dwarf have helped astronomers calculate the exact masses and sizes of the exomers under study. And also - to obtain information on the spectrum of their atmosphere, revealing its chemical composition.
So the artist imagined the conditions on the planets of the TRAPPIST-1 system / illustration RIA Novosti. Alina Polyanina.
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“By combining everything that we know about the mass of planets, their sizes, the properties of a star, we were able to calculate their density and understand how their bowels are arranged. It turned out that all seven planets are very similar in appearance and structure to Mercury, Venus, our Earth, the Moon and Mars,”continues the Trio.
These observations, in particular, indicate that at least five TRAPPIST-1 planets - b, c, d, e, f - have a rather thick and dense atmosphere, similar in its properties to the air shells of the Earth and its neighbors than to superdense gas mantle of Neptune and other giant planets.
In addition, the atmosphere d, e, f, scientists assure, contains significant amounts of steam, and the bowels of all the planets of the system, judging by their density, are almost 5% water. All of this, Trio notes, does not necessarily mean that at least one of the "seven sisters" of TRAPPIST-1 is habitable, but does not suggest that this system is absolutely incapable of supporting life.
More detailed data on the composition of the atmosphere and its possible temperature, explain Trio and his colleagues, will be available only after the launch of the follower of Hubble - the James Webb space telescope. He, as planetary scientists hope, will help us understand what complex molecules are present in the atmosphere of these worlds and whether there are traces of life there.
