The Webb telescope keeps surprising scientists every day. This time, it may have just caught a glimpse of a new world circling Alpha Centauri A—the closest Sun-like star to us.
It’s part of the Alpha Centauri triple system, a little family of three stars only about 4 light-years away. In space terms, that’s practically next door.
The possible planet is what astronomers call an exoplanet candidate, which means a planet outside our solar system that still needs confirmation. Webb’s MIRI instrument (Mid-Infrared Instrument) found it using coronography, a clever technique that blocks out a star’s blinding glare so you can spot dim objects nearby.
From what the data shows, the world could be a gas giant about the size of Saturn and moving in an orbit between 1–2 AU from its star. (One UA is the distance from Earth to the Sun.) That puts it in the habitable zone, the “just right” region where a rocky planet could have the right conditions for liquid water.
The results were published in The Astrophysical Journal Letters, and they’re the best hint yet that Alpha Centauri A might have a big planetary neighbor.
How they found it
Back in August 2024, Webb aimed its MIRI instrument at Alpha Centauri A and used coronography to hide most of the star’s light. In the cleaned-up image, a tiny, faint dot appeared—more than 10,000 times dimmer than the star and sitting about twice as far from it as Earth is from the Sun.
When astronomers looked again in February and April 2025, the dot was gone. But detailed orbital simulations (computer models of possible paths) showed that in about half of those scenarios, the planet would have been too close to the star to spot at those times.
They also compared the sighting to a possible detection in 2019 from another telescope and tested how the nearby star Alpha Centauri B could affect the orbit. The models suggest a Saturn-sized planet could keep a steady orbit between 1–2 AU even in this busy, two-star neighborhood.
Why this is such a big deal
“With this system being so close to us, any exoplanets found would offer our best opportunity to collect data on planetary systems other than our own. Yet, these are incredibly challenging observations to make, even with the world’s most powerful space telescope, because these stars are so bright, close, and move across the sky quickly,” said Charles Beichman, from the NASA’s Jet Propulsion Laboratory and the NASA Exoplanet Science Institute at Caltech’s IPAC astronomy center.
If this world is real, it would be the closest gas giant ever directly photographed around a Sun-like star. A planet with the mass of Saturn isn’t a place humans could live, but the fact that it’s in the habitable zone means stable, life-friendly orbits can exist in the Alpha Centauri triple system.
It also gives scientists a perfect target for the upcoming Nancy Grace Roman Space Telescope, launching around 2027. Roman could capture it in visible light, while Webb studies it in infrared. Together, they could reveal its size, atmosphere, brightness, and maybe even moons.
What Happens Next
Beichman also explained “This would become a touchstone object for exoplanet science, with multiple opportunities for detailed characterization by Webb and other observatories.”
And even if this discovery turns out not to be a planet, this search proves something amazing—Webb’s MIRI instrument, coronography, and advanced orbital simulations can reveal incredibly faint objects hiding right next to some of the brightest stars in the sky.
It’s a reminder that even the stars just next door might have hidden worlds… and with these tools, we are only starting to find them.