2024-07-11 06:46:17
An ocean, ice and a thick atmosphere: these are the signs of life that have been discovered on an exoplanet. These are not the only signs.
The exoplanet “LHS 1140 b”, which is about 39 light years away from Earth, could be a world covered in ice and an ocean with a cloudy atmosphere. Astronomers have discovered this using new data from the James Webb Space Telescope, as the University of Michigan writes on its website.
NASA astronomer Ryan MacDonald, who teaches at the university and helped analyze the data, said: “This is the first time we have seen evidence of an atmosphere on a rocky or icy exoplanet in the habitable zone.”
His colleague and co-author of the study, Charles Cadieux, goes one step further. “Of all the currently known temperate exoplanets, ‘LHS 1140 b’ could be our best chance of one day being able to detect liquid water on the surface of an alien world outside our solar system,” he said. According to Cadieux, this would be a breakthrough in the search for potentially habitable planets outside our solar system.
“LHS 1140 b” has been known for many years and was already considered a promising candidate for a planet on which life could exist. It is 1.7 times the size of the Earth and orbits its star in the so-called habitable zone. This is the area in which it is neither too cold nor too warm, so that liquid water can exist – a prerequisite for life.
The exoplanet could also be completely covered in ice, similar to Jupiter’s moon Europa, the researchers write. It is also conceivable that it is an ice world with a liquid ocean in the middle, since the planet always faces the same side towards its star – similar to our Earth’s moon.
The orbital period of “LHS 1140 b” is 25 days. This means that the planet is much closer to its star than the Earth is to the Sun. The fact that temperatures that would allow life to exist on it is due to the nature of the central star. It is a red dwarf star, which is smaller and cooler than our Sun.
These conditions could mean that the water of a possible ocean on “LHS 1140 b” could even be a “pleasant 20 degrees Celsius,” it is said. And what’s more: the analysis of data from the James Webb Space Telescope has shown that the planet, like Earth, could have a nitrogen-rich atmosphere.
To confirm this, the researchers say, additional observations with the telescope are necessary.
“LHS 1140 b” is not the only candidate that astronomers suspect could be potentially habitable. In the “Trapist-1” system, which is also around 40 light years from Earth, there are seven Earth-sized planets, three of which are in the habitable zone.
The star system “Kepler-62” also has Earth-sized exoplanets, “Kepler 62 e” and “Kepler 62 f”, in the habitable zone of the central star. Life would theoretically be possible there too if the other conditions, such as liquid water and oxygen, were present.