Researchers first confirmed the presence of an exoplanet using the James Webb Space Telescope. Formally classified as LHS 475 b, the planet is almost the same size as our own and is 99% the diameter of the Earth.
The research team is led by Kevin Stevenson and Jacob Lustig-Yaeger, both from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. The team decided to observe the target with the Webb Telescope after carefully examining data from the NASA Transiting Exoplanet Survey Satellite (TESS) that hinted at the existence of the planet.
The Webb Near Infrared Spectrograph (NIRSpec) easily and clearly captured the planet in just two transit observations.
“There is no doubt that the planet is there. Webb’s initial data confirms this,” Lustig-Jäger said. “The fact that it is also a small rocky planet is impressive!” Stevenson added.
Of all the telescopes in operation, only Webb is able to characterize the atmospheres of Earth-sized exoplanets. The team tried to estimate what is in the planet’s atmosphere by analyzing its spectrum. Although the data show that this terrestrial planet is almost the size of Earth, it is not yet known if it has an atmosphere.
“The telescope is so sensitive that it can easily detect a whole range of molecules, but we can’t yet draw any definitive conclusions about the planet’s atmosphere.” – Erin May, a specialist from the Applied Physics Laboratory at Johns Hopkins University.
While the team cannot deduce what is present on this exoplanet, scientists can definitely tell what is not on it. “There are some Earth-like atmospheres that we can rule out,” explained Lustig-Jäger. “It can’t have a dense, methane-dominated atmosphere like the atmosphere of Saturn’s moon Titan.”
The researchers’ findings opened up the possibility of pinpointing Earth-sized planets orbiting smaller red dwarfs. “And this is just the first of many discoveries that this telescope will make,” Stevenson said. Lustig-Yaeger agreed: “With this telescope, rocky exoplanets will be the new frontier.”
The planet LHS 475 b is relatively close, only 41 light-years away, in the constellation Octance.
The team’s results were presented at the American Astronomical Society (AAS) press conference on Wednesday, January 11, 2023.
A source: “Webb confirms its first exoplanet”, ESA