Astronomers using the Atacama Large Millimeter/submillimeter Array have captured images of the doomed red supergiant Betelgeuse. The 2023 observations reveal an irregular, bubbling surface featuring persistent hotspots that have baffled current stellar models by surviving for at least seven years.
Atacama Array Resolves the Turbulent Surface of Betelgeuse
Betelgeuse continues to draw intense scientific scrutiny. Located roughly 600 light-years away in the constellation Orion, the infamous red supergiant possesses around 20 times the mass of our sun while puffing out to roughly 800 times the sun’s radius. Its immense size allows sensitive instruments to resolve structures across its atmosphere that remain hidden in most other stars. The observations were obtained in 2023 using the Atacama Large Millimeter/submillimeter Array (ALMA) in its longest-baseline configuration, achieving a resolution of about seven milliarcseconds.
While public fascination with the star surged a few years ago due to a rapid dimming event that led some to speculate an imminent supernova, astronomers view that explosion as less immediately certain today. Even so, the star’s ultimate destiny drives ongoing research. Its eventual fate as a supernova makes it fascinating to know what it actually looks like now,
said Bill Dent, an astronomer at the European Southern Observatory and team leader for the observations.
Hotspots and Corrugated Textures Across the Stellar Atmosphere
The newly published ALMA imagery reveals an atmosphere with an average temperature of approximately 3,680 degrees Fahrenheit, alongside at least two regions significantly hotter than the surrounding plasma. One of these localized areas registers nearly 980 degrees Fahrenheit above its surroundings. The stellar surface itself is far from spherical, showing radius variations of up to about six percent, while fainter molecular emission extends several stellar radii outward into a clumpy environment containing silicon monoxide and carbon monoxide.
Researchers attribute this uneven, corrugated topography to massive convective movements within the interior. Hot plasma rising from deeper layers generates shockwaves that erupt directly into the star’s outer atmosphere, creating distinct bright and hot regions.
Seven-Year Persistence Challenges Existing Convection Models
The most surprising discovery emerged when the research team compared the 2023 data against archival observations gathered by ALMA in 2015. Rather than shifting rapidly as expected from turbulent convection models, the prominent hotspot located toward the northeast of the stellar disk appeared in nearly the exact same geographic position and maintained a similar intensity across the gap.
This longevity indicates that certain atmospheric structures can endure considerably longer than current theoretical models predict.
Investigating Potential Companion Stars and Mass Loss
Beyond internal convection, the specific orientation of these persistent hotspots provides fresh context for ongoing debates surrounding Betelgeuse. Astronomers note that the alignment adds supportive circumstantial weight to hypotheses suggesting an elusive companion star orbits the massive red supergiant, though the current submillimeter data does not establish a direct physical link.
Scientists plan to continue monitoring the star with high-resolution instrument configurations. Future campaigns aim to determine whether these fixed hotspots remain anchored over even longer periods and how their evolution dictates mass loss and structural changes in the extended atmosphere as Betelgeuse inches closer to its eventual supernova finale.
