The Alpha Centauri star system, located just four light-years from Earth, might host a giant planet in its habitable zone.
The observation of a Saturn-sized planet by the James Webb Telescope in August 2024 generated significant excitement. However, subsequent attempts to locate it in 2025 proved unsuccessful, leaving scientists puzzled.
The Alpha Centauri system captured by three different observatories. From left to right: the Digitized Sky Survey (DSS), NASA's Hubble Space Telescope, and NASA's James Webb Space Telescope. The right image shows a dot that could be a Saturn-sized planet.
Credit: NASA, ESA, CSA, Aniket Sanghi (Caltech), Chas Beichman (NExScI, NASA/JPL-Caltech), Dimitri Mawet (Caltech)
Researchers remain optimistic and plan new observations for 2026 or 2027. The disappearance might be explained by the planet's orbital motion.
These future observations could confirm the planet's existence, which would make it a major discovery. The proximity of the Alpha Centauri system makes it an ideal laboratory for studying exoplanets and their characteristics.
If confirmed, this planet would be the closest to Earth orbiting in a star's habitable zone. Although too large to host life as we know it, its discovery would open new perspectives in the search for habitable worlds.
The Alpha Centauri system, composed of three stars, is already known to host planets around Proxima Centauri. This new potential discovery reinforces the system's importance for exoplanet research.
Astronomers are already considering expanding their search to other nearby stars like Tau Ceti, despite increased difficulties. NASA's upcoming Nancy Grace Roman Space Telescope, scheduled for launch in 2027, promises to further expand our horizons in the hunt for exoplanets.
Artist's impression of a Saturn-sized planet near Alpha Centauri A, a Sun-like star located about four light-years from Earth.
Credit: NASA, ESA, CSA, STScI, Robert L. Hurt (Caltech/IPAC) Discovering exoplanets... until we find extraterrestrial life?
An exoplanet is a planet that orbits a star other than the Sun. These distant worlds can vary in size, from small rocky planets similar to Earth to gas giants like Jupiter. The first exoplanet was confirmed in 1992, opening a new field in astronomy.
Exoplanets are detected using several methods, with the transit method being the most common. This technique observes the slight dimming of a star when a planet passes in front of it. Other methods include measuring stellar wobbles caused by a planet's gravity.
Studying exoplanets helps scientists better understand planetary system formation and evolution. It also provides clues about the possibility of life elsewhere in the Universe. Recent discoveries, like those around Proxima Centauri, show that planets are common in our galaxy.
With the advent of more powerful telescopes like James Webb, astronomers hope to discover Earth-like planets in their stars' habitable zones. These advances might one day answer whether we are alone in the Universe.