James Webb Space Telescope finds its first exoplanet

12 Jan 2023

An Illustration of the exoplanet LHS 475 b, which is 41 light-years away in the Octans constellation. Image: NASA, ESA, CSA, Leah Hustak (STScI)

Researchers are viewing the space observatory’s data to determine if the planet has an atmosphere, with more exoplanet discoveries planned for the future.

The James Webb Space Telescope has discovered its first exoplanet, which is almost exactly the same size as Earth.

NASA said this newly discovered exoplanet – a planet orbiting a different star to our own sun – is relatively close, at 41 light-years away in the Octans constellation.

The planet, dubbed LHS 475 b, was observed with the space observatory’s Near-Infrared Spectrograph instrument, which NASA said captured the planet clearly with only two transit observations.

The planet appears to be 99pc of Earth’s diameter, with initial results listing it as a rocky planet. The astrophysics division director at NASA headquarters, Mark Clampin, said these initial results open the door to “many future possibilities for studying rocky planet atmospheres”.

“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,” Clampin said.

NASA said the James Webb is the only operating telescope that can categorise the atmosphere of Earth-sized exoplanets. The team behind the discovery has been assessing the transmission spectrum from James Webb to learn more about the planet.

“The observatory’s data are beautiful,” said Erin May, senior staffer at 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 researchers have not confirmed if the planet has an atmosphere, they have been able to rule out certain possibilities from the data. For example, the transmission spectrum suggests that it can’t have a pure carbon monoxide atmosphere, or one that is dominated by methane.

The exoplanet is closer to its star than any planet in our solar system, completing its orbit in only two days. However, NASA said this red dwarf star is less than half the temperature of our Sun, so researchers project the planet could have an atmosphere.

Kevin Stevenson and Jacob Lustig-Yaeger, who led the John Hopkins research team, said the results highlight the precision of the James Webb Space Telescope, the successor to the Hubble Space Telescope. The researchers expect the observatory’s powerful instruments to find more discoveries in future.

“With this telescope, rocky exoplanets are the new frontier,” Lustig-Yaeger said.

Last August, Researchers discovered an exoplanet around 100 light-years away that is in the perfect location to be a ‘water world’ full of deep oceans.

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Leigh Mc Gowran is a journalist with Silicon Republic