Space Observatory Identifies Gas Giant Orbiting Star System Nearest to Earth
In a significant discovery that could reshape the next decade of exoplanet science, a potential gas giant has been detected orbiting the closest Sun-like star to Earth – Alpha Centauri A. The breakthrough was made using the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope.
The orbit of this potential planetary neighbour is elliptical, ranging from one to two times Earth's orbital distance from the Sun. Estimates suggest that it has a mass similar to Saturn, making it a significant find in the search for exoplanets.
In August 2024, astronomers detected a faint object over 10,000 times dimmer than Alpha Centauri A, located at about twice the Earth-Sun distance. Results from further observations in February and April 2025 showed that in nearly half the scenarios, the planet would have moved too close to Alpha Centauri A, hiding it from Webb's view. However, the new Webb data, combined with the earlier hint, strengthens the case for a genuine planetary companion around Alpha Centauri A.
The Alpha Centauri system consists of three stars: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The detection of the mysterious candidate was complicated by the extra light from Alpha Centauri B, but careful subtraction of both stars' glow revealed the candidate, sparking excitement among the team.
The discovery of this potential gas giant, if verified, could make it the closest planet ever found in the habitable zone of a Sun-like star. If confirmed, it would also be the closest directly imaged planet to a Sun-like star and the most similar in temperature and age to our own gas giant planets.
The James Webb Space Telescope is expanding our ability to image exoplanets directly, something that was once nearly impossible, especially around bright and nearby stars. The discovery of planets around Alpha Centauri A and B has proven far more challenging compared to the discovery of planets around Proxima Centauri.
The presence of this potential gas giant in a binary system would challenge existing models of planet formation, survival, and stability in dynamic environments. The scientist group investigating the possibility of a gas giant around Alpha Centauri A is not explicitly named in the search results. However, such research is typically associated with teams specializing in exoplanet detection and astronomy, potentially involving collaborations linked to recent studies reported by sources like Astronews.
If the detection holds, this potential gas giant would be a significant step forward in our understanding of the universe and the potential for life beyond our solar system. The discovery could offer the closest and clearest look yet at a planetary system beyond our own.
