NASA's Webb Telescope Spots Saturn-Sized Gas Giant In Sun's Nearest Stellar System
For years, the Alpha Centauri system, comprising two Sun-like stars, Alpha Centauri A and B, and a faint red dwarf named Proxima Centauri, has been the subject of intense scrutiny and search for extraterrestrial world(s). While Proxima Centauri is already known to host at least three planets, finding a world around the more Sun-like Alpha Centauri A and B has proven a far greater challenge.
This new world, a candidate gas giant about the mass of Saturn, appears to be orbiting Alpha Centauri A at a distance of about twice that of Earth from the Sun. This puts it squarely in the star's habitable zone, i.e. the region where liquid water could potentially exist on a planet's surface. However, because this potential world is a massive gas giant, scientists say it's unlikely to harbor life as we know it. Still, the prospect of habitable moons orbiting such a planet remains a possibility.
The discovery is not without its mysteries. The object, which was first detected in August 2024, did not appear in follow-up observations conducted in early 2025. Researchers haven't been discouraged, though; simulations show that the planet's elliptical orbit could have simply taken it too close to its host star to be visible during those later checks.
PhD student Aniket Sanghi of Caltech in Pasadena, California (and the co-author on the two papers covering the research) said, "We found that in half of the possible orbits simulated, the planet moved too close to the star and wouldn’t have been visible to Webb in both February and April 2025." Nonetheless, if confirmed, this discovery would mark the closest-ever directly imaged planet to its host star and the first one found around a star so similar in age and temperature to our Sun.
