James Webb Telescope Discovers Earth-Size Rocky Exoplanet

Researchers using the James Webb Space Telescope discovered an exoplanet, a planet that orbits a star, which is roughly the same size as the Earth but a few hundred degrees warmer, NASA said Wednesday.

It was the first time an exoplanet was discovered by using the Webb Telescope since it first became fully operational in July, NASA said.

"These first observational results from an Earth-size, rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb," Mark Clampin, Astrophysics Division director at NASA Headquarters in Washington, said in a news release. "Webb is bringing us closer and closer to a new understanding of Earth-like worlds outside our solar system, and the mission is only just getting started."

NASA said the planet, named LHS 475 b, is 99% equal to the size of the Earth and close to our solar system, about 41 light years away in the constellation Octans, which is not visible in the Northern Hemisphere.

The telescope revealed the planet is a few hundred degrees warmer than the Earth, so if clouds are detected, it could lead researchers to conclude the planet is a lot like Venus, which has a carbon dioxide atmosphere and is shrouded in thick clouds.

More precise measurements are needed for the team to distinguish a pure carbon dioxide atmosphere from no atmosphere. NASA said the researchers are scheduled to get more data with upcoming observations this summer.

"There are some terrestrial-type atmospheres that we can rule out," said Jacob Lustig-Yaeger, co-leader of the research team from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. "It can't have a thick methane-dominated atmosphere, similar to that of Saturn's moon Titan."

NASA said the planet completes an orbit of its sun in just two days. Although LHS 475 b is closer to its star than any planet in our solar system, its red dwarf star is less than half the temperature of the Sun, which is considered a yellow dwarf, so researchers said it still could have an atmosphere.

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