Astronomers have found water on an exoplanet, which is twice the size of Earth. The celestial body K2-18 b may be the “best candidate for possible settlement,” currently known outside our solar system.
Scientists launched two space missions. The Kepler NASA shuttles and the Transiting Exoplanet Survey Satellite (TESS) allowed researchers not only to measure the size and orbit of the planet, but also to determine its density and soil composition.
Space scientists are unanimous in their opinion: “This is the only planet that we now know outside the solar system, with water and the atmosphere. Most importantly, the planet maintains an optimum temperature that allows the formation of living organisms. ” Angelos Ziaras, an astronomer at University College London and a lead author of one of the studies that were published in the journal Nature Astronomy, became interested in the project.
Ciaras and his colleagues suggest that water vapor found in the planet’s atmosphere can range from one hundredth of a percent to half of K2-18b. To accurately determine how much water (as well as other gases such as methane, carbon dioxide and ammonia) are contained in the atmosphere of a celestial body, more observations using space technology will be required. Astronomers plan to use the Exoplanet Large-Survey (ARIEL) telescope.
The celestial body K2-18 b is almost two times larger than the Earth and almost nine times more massive. The core of the planet consists of stone or ice, it is surrounded by a dense shell of hydrogen and other gases.
Found by Kepler in 2015, the star is in a 33-day orbit around a dim, cool red dwarf star at a distance of about 110 light-years from Earth, in the constellation Leo. The central star shines less than 3 percent brighter than our own Sun, but since K2-18b rotates too close to the central planet, it receives only 5 percent more starlight than Earth.
Some researchers call K2-18 b and similar planets “Super-Earths,” while others prefer to call them “mini-Neptunes.” Such bodies do not rotate around our Sun, despite the fact that they are the most numerous planetary objects in the Milky Way.
“I like to call them“ hybrid ”planets, these worlds with rocky cores and thick hydrogen shells,” says astronomer Benneke. “This is not a bare rock with a thin atmosphere, like on Earth, but not a giant planet like Neptune or Jupiter.”
The main thing that scientists hope to understand is the factors that lead to the formation of such planets.
Nicole Lewis, an astronomer at Cornell University who has not participated in any of the studies, notes that this is not the first time that scientists have detected signs of water vapor, clouds, and possibly even rains, in worlds outside the solar system.
K2-18 b will allow scientists to better understand the composition of colder and smaller planets. The study of such a planet will allow researchers to answer the question of how the atmospheres of planets are formed and develop in the habitable zone around red dwarfs.This is important for understanding the potential habitability of small planets the size of the Earth.
Water vapor on K2-18 b would be the best evidence that small planets in habitable zones of red dwarfs can generally have an atmosphere. Tiny red dwarfs can create an atmosphere-damaging amount of radiation that peaks at the beginning of star life, when newborn planets can be the most vulnerable. Attempts to study the alleged atmospheres of several potentially inhabited planets, including the atmosphere of a red dwarf called TRAPPIST-1, have given inconclusive results. The last probe LHS 3844 b, which was sent to the transit world of red dwarfs by a third more than ours, suggested that the planet may well have no air at all.
Astronomers have been studying transit planets for 20 years, so they have long passed the era of “surface” research. At the same time, the principles of the appearance and formation of atmospheres around such planets as K2-18 b have not yet been studied.
