Summary
Astronomers using jwst reported a candidate Saturn-like exoplanet orbiting alpha-centauri-a, the closest Sun-like star to Earth at just over four light-years. If confirmed, this would be the closest exoplanet ever detected orbiting in a star’s habitable zone. The candidate was imaged with JWST’s MIRI coronagraph at 15 microns and is consistent with a gas giant between Saturn and Jupiter in size, orbiting at ~2 AU with an estimated temperature of ~225 K. The detection remains unconfirmed: of three JWST observations in 2024-2025, the object appeared in only one, though earlier VLT data hints at the same source. Published by the seti-institute.
Key Claims
- JWST’s MIRI coronagraph detected a candidate exoplanet around alpha-centauri-a at ~2 AU separation, consistent with a gas giant (Saturn-to-Jupiter sized) at ~225 K
- The candidate would be the closest exoplanet orbiting a Sun-like star’s habitable zone, though a cold gas giant itself is unlikely to host life — moons could be targets
- Three JWST observation epochs produced only one detection; re-imaging is required to rule out artifacts or background sources
- Earlier Very Large Telescope mid-infrared observations detected a compatible source, lending credibility
- alpha-centauri-a and B’s 11-35 AU separation limits stable planetary orbits; a gas giant at 2 AU constrains planet-formation models in binary systems
- Future confirmation paths include JWST follow-up, radial velocity measurements, the nancy-grace-roman-space-telescope (2027), project-blue (dedicated Alpha Centauri imager), and the habitable-worlds-observatory
Notable Quotes
“The Alpha Centauri system will always be observed. It’s our nearest laboratory for studying exoplanets in detail.” — Dr. Julien Girard, STScI