Astronomers using the Atacama Large Millimeter/submillimeter Array have captured imaging of the red supergiant star Betelgeuse in 2023. The high-resolution observations reveal a turbulent, corrugated surface marked by persistent hotspots that endure longer than current stellar convection models predict.
Betelgeuse occupies a familiar place in both astronomical databases and public imagination. Located roughly 600 light-years away in the constellation Orion, the massive red supergiant sparked widespread curiosity a few years ago when a dramatic dimming cycle led some observers to speculate that an explosive supernova was imminent. While that catastrophic event has not materialized and scientists view an immediate explosion as less likely, the star remains under intense scientific scrutiny.
Atacama Array Observations Reveal Corrugated Structure and High Temperatures
A research team examined the doomed star using the Atacama Large Millimeter/submillimeter Array, known as ALMA, to map its turbulent atmosphere in fine detail. By utilizing the telescope array in its longest-baseline configuration, researchers achieved a resolution of approximately seven milliarcseconds, allowing them to resolve physical structures across the stellar disk that remain hidden in most other stars.
The resulting submillimeter images display an irregular, corrugated outline shaped by massive convective movements. The red supergiant carries a mass roughly 20 times that of our Sun while expanding to a radius about 800 times solar proportions. ALMA measurements show that the star’s apparent radius varies by up to six percent, while fainter molecular emissions of silicon monoxide and carbon monoxide extend several stellar radii out into an extensive, clumpy environment.
The stellar atmosphere maintains an average temperature of approximately 3,680 degrees Fahrenheit, or 2,300 Kelvin. However, the data expose at least two distinct regions significantly hotter than the surrounding plasma. One localized area sits 980 degrees Fahrenheit warmer than the ambient gas, while the brightest hotspot reaches up to about 800 Kelvin above the background temperature.
Persistent Hotspots Challenge Current Stellar Convection Models
The most surprising revelation emerged when researchers compared the 2023 ALMA observations with archive data gathered by the same telescope array in 2015. Conventional stellar models suggest that large convective structures on giant stars should evolve and dissipate rapidly. Instead, the prominent northeastern hotspot appeared in nearly the exact same geographical location across observations separated by more than seven years.
This longevity indicates that certain atmospheric structures persist considerably longer than theoretical predictions allow. Scientists attribute the uneven surface features to enormous convective currents where hot plasma rises from deep inside the star, generating shockwaves that erupt into the outer atmosphere. The orientation of these long-lived hotspots also aligns with recent suggestions that an elusive companion star orbits the supergiant, though researchers note the current data do not establish a definitive physical connection.
Expert Insights on the Doomed Star’s Evolutionary Stage
Astronomers emphasize that studying the star in its current state provides vital baseline data for understanding the final phases of stellar evolution. As the supergiant nears the end of its life cycle, capturing its surface dynamics offers a window into the physics governing massive stars prior to core collapse.
That eventual explosion will occur as the star ends its life, according to research team statements. The study detailing these findings has been accepted for publication in the journal Astronomy & Astrophysics and remains accessible on the arXiv preprint repository.
International Collaboration Behind the Submillimeter Imaging Facility
The Atacama Large Millimeter/submillimeter Array operates as an international astronomy partnership. The facility unites the European Southern Observatory, the U.S. National Science Foundation, and Japan’s National Institutes of Natural Sciences in cooperation with the Republic of Chile.
| Partner Organization | Primary Region |
|---|---|
| European Southern Observatory | Europe |
| National Science Foundation & National Research Council | North America |
| National Institutes of Natural Sciences & Academia Sinica | East Asia |
Construction and operations are managed jointly by the European Southern Observatory on behalf of its member states, the National Radio Astronomy Observatory for North America, and the National Astronomical Observatory of Japan for East Asia, with unified management provided by the Joint ALMA Observatory.
Future Monitoring Plans for the Supergiant Atmosphere
Astronomers intend to maintain high-resolution monitoring with ALMA to determine whether the hotspots remain fixed over even longer intervals. Future investigative goals include tracking how these persistent structures influence mass loss and mapping the complex dynamics of the star’s extended atmosphere until the supergiant ends its life in a supernova explosion.
