The James Webb telescope confirms the existence of its first exoplanet

The James Webb telescope confirms the existence of its first exoplanet

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  • It is about the same size as Earth and is 41 light years away.

The James Webb Space Telescope has confirmed the existence of its first exoplanet, which is nearly the same size as Earth, rocky, and 41 light-years from Earth.

The existence of the exoplanet, classified as LHS 475 b, was suggested by data from NASA’s TESS satellite, so the researchers decided to observe the object with James Webb, whose near-infrared spectrograph clearly captured that it was an exoplanet. planet outside the solar system.

The research team was led by Kevin Stevenson and Jacob Lustig-Yaeger of the Johns Hopkins University Applied Physics Laboratory (USA) and the results were presented at the meeting of the American Astronomical Society.

first results

LHS 475 b is 99% the diameter of Earth and lies relatively close, just 41 light-years away, in the constellation Octans.

“There is no doubt that the planet is there. Webb’s pristine data validates it,” said Lustig-Yaeger, quoted in a statement from the European Space Agency (ESA).

“These first observational results for a rocky, Earth-sized planet open the door to many future possibilities for studying” their atmospheres with Webb, said Mark Clampin, director of NASA’s Division of Astrophysics.

sensitive telescope

Of all the telescopes in operation, only Webb is capable of characterizing the atmospheres of Earth-sized exoplanets, so the team tried to assess that of the new exoplanet by analyzing its transmission spectrum.

The telescope is “so sensitive that it can easily detect a number of molecules, but we cannot yet draw definitive conclusions about the planet’s atmosphere,” Lustig-Yaeger explained.

Although the team cannot conclude what is present, they can say what is not, and they rule out the existence of some thick methane-dominated atmospheres, similar to that of Saturn’s moon Titan.

more accurate measurements

Although the planet may not have an atmosphere, there are some atmospheric compositions that have not been ruled out, such as one of pure carbon dioxide.

“Counterintuitively, a 100% carbon dioxide atmosphere is much more compact and difficult to detect,” Lustig-Yaeger said.

So the team needs even more precise measurements to distinguish an atmosphere of pure carbon dioxide from no atmosphere at all. The researchers are scheduled to obtain additional spectra with new observations this summer.


Webb also revealed that the planet is a few hundred degrees warmer than Earth, so if clouds are detected it could lead researchers to conclude that it is more like Venus, that it has an atmosphere of carbon dioxide and is perpetually shrouded. in thick clouds.

The researchers also confirmed that the planet completes one orbit in just two days, information that was revealed almost instantly by Webb’s precise light curve.

dwarf stars

Although LHS 475 b is closer to its star than any other planet in the Solar System, its red dwarf star is less than half the temperature of the Sun, so the researchers project that it could still harbor an atmosphere.

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The researchers’ findings have opened up the possibility of locating Earth-sized planets orbiting smaller red dwarf stars, and further highlight “the precision of James Webb’s instruments,” Stevenson said.

For Lustig-Yager, thanks to James Webb, “rocky exoplanets are the new frontier”.

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