By Will Dunham
WASHINGTON (Reuters) – Scientists have seen a planet orbiting a star relatively close to our solar system, possibly providing the best opportunity to study the atmosphere of a rocky Earth-alien world – the kind of research that hunts for extraterrestrial life can help.
The researchers said on Thursday that the planet, named Gliese 486 b and classified as ‘super-earth’, is not itself a promising candidate as a refuge to life. It is considered inhospitable – hot and dry like Venus, with possible rivers of lava flowing on the surface.
But its proximity to Earth and its physical properties make it well-suited for a study of its atmosphere with next-generation space-based and ground-based telescopes, starting with the James Webb Space Telescope that NASA planned for a launch in October. It can provide scientists with information to decipher the atmosphere of other exoplanets – planets outside our solar system – including the lives that could possibly live.
“We say that Gliese 486 b will immediately become the Rosetta Stone of exoplanetology – at least for terrestrial planets,” said astrophysicist and co-author José Caballero of Centro de Astrobiología in Spain, referring to the ancient stone slab that helped experts has. To decipher Egyptian hieroglyphs.
Scientists have discovered more than 4,300 exoplanets. Some were large gas planets like Jupiter. Others were smaller, rocky, earthy worlds, the kind that are considered candidates to house life, but currently available scientific instruments tell us little about their atmosphere.
“The exoplanet must have the right physical and orbital configuration to be suitable for atmospheric exploration,” said planetary scientist Trifon Trifonov of the Max Planck Institute of Astronomy in Germany, lead author of the research published in the journal Science.
A ‘super-Earth’ is an exoplanet with a mass larger than our planet, but significantly smaller than our solar system’s giant ice Uranus and Neptune. The mass of Gliese 486 b is 2.8 times that of Earth.
This is about 26.3 light-years in our heavenly neighborhood – the distance that light travels within a year, 9.5 trillion miles (9.5 trillion miles), from Earth, making it one of the nearest exoplanets. It orbits a ‘red dwarf’ star that is smaller, cooler and less bright than our sun, with about a third of the mass.
The planet orbits very close to its home star and radiates heavily. Like Earth, it is a rocky planet and is thought to have a metal core. The surface temperature is about 430 degrees Celsius and the gravity of the surface can be 70% stronger than the earth.
“Gliese 486 b cannot be habitable, at least not as we know it here on earth,” Trifonov said. “The planet may only have a soft atmosphere, if any. Our models are consistent with both scenarios because stellar radiation tends to vaporize atmospheres, while the planet’s gravity is strong enough to maintain it at the same time.”
Nevertheless, Gliese 486 b may be ideal for studying the atmosphere of an Earth-like planet using instruments on the James Webb Space Telescope and the future Extremely Large Telescope, an astronomical observatory now being built in Chile.
The chemical composition of an atmosphere can tell a lot about a planet and its habitability. Scientists are interested in combining gases in the atmosphere of terrestrial exoplanets, with a mixture of oxygen, carbon dioxide and methane like that of our own planet, which could be a possible indication of life.
‘Everything we learn with the atmosphere of Gliese 486 b and other terrestrial planets will be applied in a few decades to the detection of biomarkers or biosignatures: spectral features on the atmosphere of exoplanets that can only be attributed to extraterrestrial life. , “Caballero added.
(Reporting by Will Dunham, Editing by Rosalba O’Brien)