In a First, 'Super-Earth' Planet Shows It Could Have an Atmosphere

"Scientists say they have detected promising signs that a planet orbiting a star 49 light-years from Earth could have an atmosphere," reports CNN, "making it potentially suitable for life."




Called LHS 1140b, the object is about five times the mass of our planet, or a "super-Earth." This planet orbits around its star in the "Goldilocks zone," also known as the habitable zone, meaning its surface temperature is not too hot or too cold for liquid water to exist... "It appears to be consistent with Earth, meaning it might have an iron core and a silicate mantle, plus some sort of low-density component, which is probably a combination of water and, now we know, an atmosphere," [said Collin Cherubim, a planetary scientist and lead author of a paper on the finding, published July 16 in the journal Science]... If further observations confirm the findings, LHS 1140b would mark the first discovery of an atmosphere on a rocky planet in the habitable zone of another star...

There is no evidence of life or a life-supporting atmosphere on LHS 1140b now, but Cherubim said he believes it's a formidable candidate for potential signatures of extraterrestrial life. "I think it's the best place to look for life outside the solar system at this point," he said. "It's mostly rocky, it's at the right temperature to support liquid water on the surface, and it has an atmosphere — those are the three key ingredients we look for..." Confirming the existence of an atmosphere on a rocky planet orbiting a red dwarf would be particularly exciting, Cherubim said, because the possibility of that happening is an open question in astronomy. "Can rocky planets have atmospheres around red dwarfs? This is the first bona fide yes," he said. "It's kind of a sigh of relief for a lot of us. But the jury's still out. Maybe this is a weird planet, and it's an oddball, or maybe it's the first of many. We don't know yet."

Now "The James Webb Space Telescope is going to look at it," Cherubim told CNN, and "Hubble's going to look at it. Basically, everybody who can see it is going to be training their eyes on it."

Michaël Gillon, research director of the Astrobiology Research Unit at Belgium's University of Liège warned CNN that no definitive proof exists that LHS 1140b possesses a substantial atmosphere. But if the detection of helium can be confirmed, the implications would be profound. "Until now, we had only limited evidence for atmospheres on temperate rocky exoplanets. Demonstrating that LHS 1140 b has retained a substantial atmosphere over billions of years would show that at least some habitable zone Super-Earths around red dwarfs can survive the intense early activity of their host stars."

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