NASA’s Webb spots mysterious planet orbiting star Near Alpha Centauri

This artist’s concept depicts a gas giant planet that NASA’s Webb telescope found strong evidence for around Alpha Centauri A (upper left). The Alpha Centauri system is home to three stars including Alpha Centauri B (upper right). Our Sun is shown as a small dot of light between those two stars. (Image: NASA)

NASA’s James Webb Space Telescope has captured signs of a possible giant planet in Alpha Centauri A. The star sits in the stellar system closest to our Sun, just four light-years away from Earth. The discovery, if confirmed, could change how we view exoplanets around Sun-like stars.

Closest gas giant found using Webb's MIRI

The suspected gas giant was detected using Webb’s Mid-Infrared Instrument (MIRI). The data came from special images taken in August 2024. The team used a coronagraph to block Alpha Centauri A’s bright light. This let them study objects nearby that are usually hidden.

Astronomers spotted a dim object more than 10,000 times fainter than the star. It was located about twice the distance between Earth and the Sun. The object is not likely to be an asteroid, galaxy or camera glitch, researchers said.

The planet-like object was missing in follow-up images taken in February and April 2025. This has raised fresh questions and left experts puzzled.

Observations of the Alpha Centauri triple star system: From left, the ground-based Digitized Sky Survey shows all three stars as a single source of light; NASA’s Hubble resolves two Sun-like stars; the MIRI instrument on NASA’s Webb blocks the bright glare from one star, revealing a potential planet. (Image: NASA)

Alpha Centauri system holds strong interest

Alpha Centauri is a triple star system visible only from the Southern Hemisphere. It includes Alpha Centauri A and B—both Sun-like stars and Proxima Centauri, a faint red dwarf. Three planets are already confirmed around Proxima, but Alpha Centauri A and B have remained uncertain.

Alpha Centauri A is the third brightest star in our night sky. Finding planets in its orbit has been a long-term goal. Experts say any confirmed exoplanet in this system would be a major target for future missions.

Three increasingly close views from NASA’s Webb show how a possible planet was revealed in the Alpha Centauri triple star system. A coronagraphic mask placed over one of the system’s two Sun-like stars blocks its bright glare (middle), and the removal of additional light interference (right) unveils the candidate planet. (Image: NASA)

"Disappearing planet" puzzles scientists

The research team used computer models to test millions of possible orbits. They combined data from when the object was seen and when it was not.

“We are faced with the case of a disappearing planet,” said Aniket Sanghi, a PhD student at Caltech. He is a co-lead author on the two papers describing the research.

Despite the mystery, the team remains hopeful. The star system’s closeness gives scientists a rare chance to study planetary systems beyond our own.

The findings have been accepted for publication in The Astrophysical Journal Letters. Further observation is expected to confirm if this curious object is a true exoplanet or something else entirely.