NASA’s James Webb telescope discovers its first Earth-sized exoplanet.

Why in news?

• The National Aeronautics and Space Administration’s (NASA) James Webb Space Telescope (JWST) discovered its first exoplanet, a planet that orbits another star, formally classified as LHS 475 b, which is reportedly almost the exact size of Earth, clocking in at 99% of Earth’s diameter.
• The planet is rocky and almost precisely the same size as Earth, but orbits around its star in only two days.
• LHS 475 b, located in the constellation Octans, is only 41 light-years away.
• Researchers used NASA’s James Webb Space Telescope’s Near-Infrared Spectrograph (NIRSpec) to observe exoplanet LHS 475 b on 31st August 2022. The team’s results were presented at a press conference of the American Astronomical Society (AAS) on 11th January 2023.

Key Points: 

• The team chose to examine this target with Webb after carefully reviewing targets of interest from NASA’s Transiting Exoplanet Survey Satellite (TESS), which highlighted the planet’s existence.
• With just two transit observations, Webb’s Near-Infrared Spectrograph (NIRSpec) was able to capture the planet clearly.
• Only Webb is able to characterise the atmospheres of Earth-sized exoplanets among all other active telescopes.
• By examining the transmission spectrum of the planet, scientists made an effort to assess what is included in its atmosphere.
• The precise light curve of Webb almost immediately showed the planet’s two-day orbital period.
• 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, therefore researchers project it still could support an atmosphere.