Scientists detect atmosphere on Earth-like exoplanet
Scientists have detected an atmosphere on the exoplanet LHS 1140 b, located 40 light-years away and discovered in 2017, Spanish news agency EFE reported on Thursday. The finding marks an important step in the search for Earth-like planets beyond our solar system that could potentially support life.
The discovery, made by a large international team of researchers from leading U.S. universities and published in the journal Science, provides the strongest evidence so far for the existence of worlds with temperatures and compositions similar to Earth's that may be capable of hosting life, CE Report quotes AGERPRES.
Astronomers have previously detected atmospheres on exoplanets similar to those of Uranus or Neptune, but never one resembling Earth's.
LHS 1140 b has a mass about 5.6 times that of Earth and a radius roughly 1.7 times larger. It orbits an older red dwarf star every 24.7 days.
Its characteristics match those of a rocky world with a composition similar to Earth's, receiving about 42% of the stellar radiation that Earth receives from the Sun.
This has led scientists to conclude that its temperature could allow liquid water to exist, although it remains unknown whether planets of this size have Earth-like surfaces.
"We believe, and the new data appear to confirm, that LHS 1140 b is a planet halfway between an ocean world—completely covered by water with oceans hundreds of kilometers deep—and an icy giant like Uranus or Neptune, whose composition is dominated by hydrogen," said José Antonio Caballero, an expert at the Spanish Center for Astrobiology.
Researchers first detected signs of helium escaping from LHS 1140 b's atmosphere in 2024 using the Magellan Clay Telescope at Las Campanas Observatory in Chile.
"Helium provided clear evidence of an atmosphere on an exoplanet in the habitable zone. It was incredibly exciting to analyze the transit spectra and gradually realize the significance of what we were seeing," said Shreyas Vissapragada of the Carnegie Observatories in California.
According to the researchers, the planet has an upper atmosphere dominated by helium and poor in hydrogen, while heavier elements, including water, may remain trapped closer to the surface.
Scientists also studied another planet in the same system, LHS 1140 c, which is smaller and exposed to stronger radiation. However, they found no evidence of an atmosphere there.
"At last! It was about time we detected signs of an atmosphere on an Earth-like planet. LHS 1140 b had always been one of the best candidates, although previous attempts had failed," Caballero said, expressing confidence that many more such discoveries will follow. "This is the first detection, but there will be many more."
Photo: Wikipedia
