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NASA's James Webb Telescope Finds Its First Exoplanet, a Major Milestone

The world isn't too far off and nearly the exact same size as Earth.

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Eric Mack Contributing Editor
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Eric Mack
2 min read
An illustration of the exoplanet LHS 475 b.

An illustration of the exoplanet LHS 475 b.

NASA, ESA, CSA, L. Hustak (STScI)

The James Webb Telescope has been operating for less than a year, but Wednesday brought news of the first exoplanet to be confirmed using the next-generation space observatory from NASA and the European Space Agency. 

The rocky, Earth-like world, named LHS 475 b, has almost exactly the same diameter as our planet and is located just 41 light-years away, which is very close on a cosmic scale. The team used Webb to observe the system around red dwarf star LHS 475 after data from NASA's Transiting Exoplanet Survey Satellite (TESS) hinted there may be a planet circling the small sun. 

"There is no question that the planet is there. Webb's pristine data validate it," Jacob Lustig-Yaeger from the Johns Hopkins University Applied Physics Laboratory, who helped lead the research, said in a statement. "With this telescope, rocky exoplanets are the new frontier."  

There's been lots of excitement among astronomers over Webb's potential for taking a closer look at exoplanets to analyze the composition of their atmospheres, which may hint at the potential for habitability and even signs of life. 

In the case of LHS 475 b, however, the scientists say they need more data to be able to draw any conclusions on that front.

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"There are some terrestrial-type atmospheres that we can rule out," Lustig-Yaeger explained. "It can't have a thick methane-dominated atmosphere, similar to that of Saturn's moon Titan."

Scenarios that haven't been ruled out, however, include a world with no atmosphere, or one that's 100% carbon dioxide -- and either of those options clearly isn't good for the prospect of life as we know it. 

There are some other pretty serious strikes against the potential habitability of LHS 475 b. While its star isn't nearly as hot as our sun, for instance, the planet orbits so close in that it completes an orbit in just two days and has temperatures that are likely a few hundred degrees hotter than Earth. 

Nonetheless, the find represents a major milestone for Webb, according to team co-leader Kevin Stevenson.

"It is only the first of many discoveries that it will make."