James Webb Telescope Detects Potential Gas Giant Exoplanet Just 4 Light-Years Away

New observational evidence from the James Webb Space Telescope (JWST), which has yet to launch, may change that. JWST astronomers have found tantalising hints of an orbiting gas giant around Alpha Centauri A, the closest Sun-like star to us. Located just four light-years away in the Alpha Centauri triple-star system, the potential planet sits within the star's habitable zone — the region where liquid water could exist — but its gas giant nature makes it inhospitable to life. Even so, its location and distinctiveness make the detection among the most captivating detections in exoplanetary exploration prior.

JWST Unveils Possible Closest Sun-Like Star Exoplanet, Awaiting Confirmation

According to a NASA report, this was done with the JWST Mid-Infrared Instrument (MIRI) using a coronagraphic mask to block out stellar glare. This method caught sight of an object which is almost 10,000 times fainter than Alpha Centauri A and at a separation of around two astronomical units. If upheld, it would be the nearest exoplanet to a similar being ever pictured and, moreover, the first healthy globe discovered in direct significance.

Researchers noted that while Alpha Centauri already hosts two confirmed planets around the red dwarf Proxima Centauri, no planet has yet been confirmed around Alpha Centauri A. Follow-up JWST observations did not capture the planet again, possibly because it was too close to the star during the imaging. Computer simulations support this possibility.

The team wants to look for more evidence using both JWST and the yet-to-be-launched Nancy Grace Roman Space Telescope, due in May 2027. Confirmation would represent a watershed moment in planetary system science, where astronomers are looking into embryonic solar systems around other stars.

Researchers said the potential planet's existence in such a dynamic binary star system could challenge current models of planetary formation and survival. Two papers detailing the findings have been accepted for publication in The Astrophysical Journal Letters.