This discovery is considered a significant step forward in the search for potentially habitable worlds , according to The Guardian on July 16. LHS 1140b is located about 49 light-years from Earth and orbits a red dwarf star in the constellation Cetus. Discovered in 2017, this planet has a mass approximately 5.6 times that of Earth and a radius about 70% larger than Earth's.
Illustration of the planet LHS 1140b - a potential candidate in the search for extraterrestrial life.
PHOTO: AFP
Previously, scientists have detected atmospheres around giant gas planets outside our solar system, as well as some planets smaller than Neptune. Many atmospheric features have also been observed around rocky planets, but not within the habitable zone (the Goldilocks zone).
"This is the first time the atmosphere of a rocky planet located in the habitable zone outside our solar system has been confirmed by actual observation," according to Dr. Collin Cherubim, lead author of the study.
"This is a really exciting discovery , as LHS 1140b becomes one of the most promising experiments to study the possibility of habitability outside the solar system," Cherubim added.
The research team said that LHS 1140b resembles Earth in several respects, such as its rocky composition and overall temperature conditions. According to Cherubim, LHS 1140b possesses many of the elements necessary for a potentially habitable environment, including a relatively rocky planet, a temperature suitable for maintaining liquid water, and an atmosphere sufficient to limit water evaporation into space, while also protecting the surface from harmful radiation.
However, this planet also has many differences. For example, it is tidally locked, meaning one side may always face its host star, and it may contain more water than Earth and possess a very different atmosphere.
Another important factor is that LHS 1140b's host star is relatively quiet. Although it's a red dwarf – a type of star that typically emits intense radiation and can erode the atmospheres of nearby planets – this star experiences far fewer violent outbursts than many similar stars. "So this is really an interesting place to continue observing, especially to look for signs of life," Cherubim said.
Professor of astrophysicism Jayne Birkby at the University of Oxford (UK) considers this a significant discovery. According to her, red dwarfs are the most common type of star, so rocky planets orbiting them are important targets in the search for habitable worlds. However, many red dwarfs are so active that they can strip the atmospheres of orbiting planets.
"This makes the discovery of the atmosphere around LHS 1140b a crucial step in understanding what a habitable planet near a red dwarf would be like," according to Birkby. She also suggests that changes in atmospheric signals could help scientists understand how the planet's atmosphere responds to ultraviolet radiation from its host star, as well as the impact of this process on surface conditions.