[ad_1]
For the first time, scientists have detected water vapor and perhaps even clouds of liquid water that are raining in the atmosphere of a strange exoplanet located in the habitable zone of its host star about 110 light-years from Earth.
A new study on K2-18b, an exoplanet discovered in 2015, orbits around a red dwarf star close enough to receive roughly the same amount of radiation from its star as Earth receives from our sun.
Previously, scientists had discovered giant gases containing water vapor in their atmosphere, but it is the least massive planet in the world to have detected water vapor in its atmosphere. atmosphere. This new document even goes so far as to suggest that the planet is hosting clouds that make liquid water rain.
"The detection of water vapor was relatively clear enough early," Björn Benneke, professor at the University of Montreal's Exoplanets Research Institute, told Space.com. . So he and his colleagues developed new analytical techniques to show that clouds of liquid water droplets probably exist on K2-18 b. "It's kind of the" holy grail "of studying extrasolar planets … a proof of liquid water," he said.
This study, which has not yet been peer-reviewed, was published on Tuesday, September 10 in the preprinting journal arXiv.org.
Related: these 10 exoplanets could be home to extraterrestrial life
A strange world
Because this study has found evidence of liquid water and hydrogen in the atmosphere of this exoplanet and that it is in the habitable zone, it is possible that this world is habitable. Previous studies have shown that other gases essential to life, as we know them, in the hydrogen-rich atmospheres of some planets.
Such studies have suggested that planets with hydrogen-rich atmospheres could harbor some life forms, Benneke said. However, the great atmosphere of K2-18b is extremely thick and creates conditions of high pressure, which "probably prevents life as we know it from existing on the surface of the planet", reads in A press release.
Thus, although Benneke does not rule out the possibility that this exoplanet may, in theory, support some kind of life, there is "certainly not an animal crawling around this planet," Benneke said. This is especially true given the fact that "there is nothing to crawl" because the planet does not really have a surface, he added.
"Most of this planet, in volume, represents the vast majority of this gaseous envelope," he said. As Benneke has described, the planet is probably a kind of potentially rocky core surrounded by a huge envelope of gaseous hydrogen containing water vapor.
Although these researchers found evidence of liquid water clouds on K2-18B, due to its lack of surface, precipitation could not accumulate on the planet. As precipitation passes through the thick layer of gas surrounding the planet's core, it would become so hot that the water would evaporate into the clouds where it would condense and fall back, said Benneke.
Without a real surface, so to speak, landing on the planet would also be almost impossible, especially because the gas is so thick and has incredibly high pressure that any spaceship created by the Earth sent there would be destroyed.
"There are millions of pressure bars, it would just be crushed and crushed," said Benneke.
The birth of K2-18 b?
Benneke suggests that eventually this planet formed by the rock accumulating huge amounts of gas, "like a vacuum cleaner," he said. This accumulation of gases would have more than doubled the radius of the planet and multiplied by eight its volume. (Today, for comparison, K2-18b is about nine times larger than Earth and about twice as large.)
To arrive at these conclusions, the research team analyzed data from Hubble Space Telescope observations made between 2016 and 2017 on the planet K2-18b passing its star eight times. This technique allows scientists to detect distinct signatures of molecules such as water in the atmosphere of a planet.
This team plans to further extend this research by studying the K2-18B with NASA's James Webb Space Telescope, which is expected to be launched in 2021.
This type of research, said Benneke, has the ultimate goal of "being able to study true real planets, similar to the Earth".
"We are not there yet," he said, but "it's really exciting."
Follow Chelsea Gohd on Twitter @chelsea_gohd. Follow us on twitter @Spacedotcom and on Facebook.
Sign up for the MACH newsletter and follow NBC News MACH on Twitter and Facebook and Instagram.
[ad_2]
Source link