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James Webb Space Telescope finds its first exoplanet

The newly discovered planet, known as LHS 475 b, is close in size to Earth but is a few hundred degrees warmer.

(CN) — The James Webb Space Telescope has reached another scientific milestone with the discovery of its first exoplanet.

NASA’s high-powered infrared space telescope, launched in December 2021, has already provided astonishing images of the formation of a new star and Saturn’s moon Titan, but until now it had not discovered a new planet.

On Wednesday, NASA released its initial findings of the newly discovered rocky exoplanet, formally called LHS 475 b, which is almost identical in size to Earth.

A team led by John Hopkins researchers Kevin Stevenson and Jacob Lustig-Yaeger used previous data collected by NASA’s Transiting Exoplanet Survey Satellite, also know as TESS, to search for the new planet.

Using Webb’s Near-Infrared Spectrograph, or NIRSpec, the team was able to easily identify the planet by observing the changes in light as it orbits its star.

“These first observational results from an Earth-size, rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb,” said Mark Clampin, director of the astrophysics division at NASA headquarters in Washington, in a statement. “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.”

Webb can make such discoveries because its instruments allow it cover longer wavelengths of lights than its predecessor, the Hubble Space Telescope, making it the only operating telescope capable of parsing the atmospheres of Earth-size exoplanets.

LHS 475 b’s atmosphere or possible lack thereof is of great interest to researchers in their attempts to better understand the new exoplanet.

“The observatory’s data are beautiful,” said Erin May of the Johns Hopkins University Applied Physics Laboratory. “The telescope is so sensitive that it can easily detect a range of molecules, but we can’t yet make any definitive conclusions about the planet’s atmosphere.”

While still unsure about the planet’s atmosphere, researchers can rule out the existence of a thick methane atmosphere like Saturn’s moon Titan and said there are several possible atmospheric compositions.

One possibility is that because the planet is a few hundred degrees warmer than Earth, it could have a hard-to-detect carbon dioxide atmosphere like Venus, which is covered in thick clouds.

While similar in size to Earth, the planet is closer to its star than any other planet in our solar system and completes its orbit in just two days. However, because its star is only half the temperature of Earth’s sun, researchers believe it is still possible for the exoplanet to have an atmosphere.

“We’re at the forefront of studying small, rocky exoplanets,” Lustig-Yaeger said. “We have barely begun scratching the surface of what their atmospheres might be like.”

To determine if the exoplanet has a pure carbon dioxide atmosphere or no atmosphere at all, researchers will need more precise data, which they are expected to get this summer with further observations.

The exoplanet discovery was not the only Webb-related news on Wednesday, as NASA also announced the space telescope had uncovered a star formation and captured images of a dusty disk that surrounds a nearby red dwarf star.

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