The vanishing planet: a ghost in our nearest solar neighbor

Space · Published 23 October 2026 Swipe more like this →

In short: In August 2024, the James Webb Space Telescope spotted a faint object orbiting Alpha Centauri A, our closest Sun-like neighbor. By early 2025, it had vanished. Is it a celestial mirage, or did the planet simply hide behind the blinding glare of its parent star?

The Alpha Centauri system, located just 4 light-years away, is a triple-star complex. While three planets orbit the red dwarf Proxima Centauri, finding worlds around the Sun-like stars Alpha Centauri A and B has been notoriously difficult. In August 2024, Webb's Mid-Infrared Instrument (MIRI) detected a source roughly 10,000 times dimmer than the primary star. This object, estimated to be a gas giant with a mass similar to Saturn, appeared to orbit at a distance between one and two times the Earth-Sun distance, placing it within the habitable zone.

Despite the compelling evidence published in The Astrophysical Journal Letters, the object disappeared from view during follow-up observations in February and April 2025. This disappearance doesn't necessarily invalidate the initial discovery.

Orbital simulations suggest that the planet may have moved into a position where the star's intense glare overwhelmed the telescope's ability to separate the two signals. Observing this star is extremely difficult due to the high contrast ratio, as Alpha Centauri A ranks as the night sky's third most luminous star. To solve this mystery, astronomers are looking toward the upcoming Roman Space Telescope. Unlike Webb, which operates in the infrared, Roman will utilize a new coronagraph to observe the system in visible light. This shift in wavelength and technology offers a second chance to confirm whether our nearest solar twin truly hosts a gas giant, providing a rare opportunity to study a planetary system other than our own.

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