LHS 475 b: This is the name given to the first exoplanet discovered by scientists using the James Webb telescope. It was the satellites that tracked Kevin Stephenson and Jacob Lustig Yeager, both Johns Hopkins University study leaders, and their colleagues. Then they used the telescope and were able to “simply” discover.
“There is no doubt that the planet exists,” Lustig-Yaeger said in a NASA press release. “New data from WEBB confirms this. And the fact that it is a small and rocky planet makes it very impressive for an observatory.” It is also remarkable that the size of the planet is almost the same as ours. Its diameter will be 99% of the Earth’s diameter. The new exoplanet is relatively close to Earth – 41 light-years away – and is said to belong to the Octant system.
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According to Mark Clampin, chief astrophysicist at NASA, the discovery opens the door to “many future opportunities to study other rocky planets” using the Webb telescope. “Webb is bringing us closer and closer to a new understanding of Earth-like worlds beyond our solar system, and our mission is just beginning.”
The Webb telescope is the only one that can be used to identify Earth-sized exoplanets. The atmosphere around it can then also be mapped, although in the case of LHS 475 b it is not yet clear what that is. “There are some Earth-like atmospheres that we can rule out,” says Lustig-Yaeger. “A thick, methane-dominated atmosphere, like that of Saturn’s moon Titan, cannot sustain it.”
A planet’s atmosphere is the sum of the gases around it. In the case of Earth, this is also sometimes referred to as the atmosphere. Every planet in the solar system has one, but scientists suggest that the discovered exoplanet may not contain another. Although it could also be a pure carbon dioxide atmosphere. “It’s more compact and harder to spot,” says Lustig-Yaeger.
What else scientists have noticed: The exoplanet is hundreds of degrees warmer than Earth. If clouds are seen, the planet could look more like Venus, a planet with a carbon dioxide atmosphere that is constantly shrouded in dense clouds. “But we’re just beginning to look at those small, rocky exoplanets,” Lustig-Yaeger confirms. In the future, the knowledge gained will make it possible to get to know the atmospheres faster.
Even more surprising is that LHS 475 b orbits its star in two days. It is closer to its star than the planets in our solar system, but the red dwarf star is less than half as hot as the sun. So it is not impossible that this dwarf star also has an atmosphere.