ALMA Captures Long-Lived Hot Spots on Betelgeuse's Surface

Astronomers using the Atacama Large Millimeter/submillimeter Array have released new images of Betelgeuse that reveal long-lived hot spots on the surface of the famous red supergiant.

The observations, reported on August 24, 2026, show fiery features that persist over time scales longer than earlier models had predicted. Betelgeuse, located in the constellation Orion, is a variable star that has drawn intense interest since its unexpected dimming episodes in recent years.

ALMA's high-resolution millimeter-wave imaging allows researchers to resolve surface structures that optical telescopes struggle to separate from the surrounding atmosphere. The hot spots appear linked to large-scale convective cells that bring hotter material from the star's interior to the photosphere.

These findings help constrain models of mass loss and the final evolutionary stages of massive stars. Red supergiants shed material through stellar winds; understanding the surface drivers of that process is essential for predicting the star's eventual supernova.

The data also contribute to the broader effort to map temperature and density variations across Betelgeuse's extended atmosphere. Previous campaigns had captured snapshots; the new ALMA results emphasise the longevity of certain features.

Betelgeuse remains a key laboratory for stellar astrophysics. Its relative proximity and large angular size make it one of the few stars whose surface can be imaged in detail. Continued monitoring with ALMA and other facilities will track how these hot spots evolve and whether they influence the star's overall brightness variations.