American scientists with the support of European colleagues for the first time experimentally confirmed the presence of water vapor in the atmosphere of a planet outside the solar system. It is reported by the journal Nature Astronomy.
The discovery was made on the exoplanet K2-18b, which is located in the "habitable zone" of its star - as astronomers call the area where water can exist in liquid form and there are prerequisites for the origin of life.
Researchers from the University of California at Los Angeles, together with specialists from the European Research Council and the British Council for Scientific and Technical Equipment, collected images taken by the Hubble telescope in 2016-2017 and applied their own algorithms to them for spectral analysis of light passing through atmosphere of the planet.
According to the results of the experiment, scientists came to the conclusion that K2-18b contains water vapor, as well as free hydrogen and helium. Researchers note that in order to determine the proportion of water vapor in the planet’s atmosphere, as well as detect other substances in it, such as nitrogen or methane, additional studies are needed.
According to the authors of the experiment, the detection of water in the atmosphere of this planet is extremely important, since it brings humanity closer to the answer to the fundamental question of whether our Earth is unique.
At the same time, scientists warn: it would be incorrect to consider the planet K2-18b “Earth 2.0” - the mass of this celestial body is much higher than ours, and the composition of the atmosphere there is completely different.
The described exoplanet in the orbit of the red dwarf K2-18 is located in the constellation Leo at a distance of about 110 light years from the Sun. The celestial body was discovered in 2015 by the Kepler apparatus along with several hundred more so-called super-earths - planets whose mass exceeds the mass of the Earth, but is much smaller than the mass of gas giants such as Neptune.
According to Dr. Ingo Waldman of University College London, the discovery of water on K2-18b can only be a prologue to a number of such discoveries that are likely to happen in the coming decades. He recalled that super-earths are the most common planets in the known region of the universe, and red dwarfs are the most common stars.
The next stage of the research program is expected to start in 2021 - then it is planned to launch the James Webb Space Telescope, which will carry much more sensitive instruments on board and will be able to more accurately determine the composition of the atmosphere. In addition, scientists expect that in 2028 the telescope will begin to send detailed images of many exoplanets to Earth.