Astronomers Mapped Persistent Hot Spots on Betelgeuse
High-resolution observations reveal long-term surface activity on the red supergiant.
Updated on Oct. 6, 2026 in Space
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Astronomers have captured new high-resolution images of the red supergiant Betelgeuse using the Atacama Large Millimeter/submillimeter Array. The data confirms the existence of two persistent hot patches on the star's surface that have remained stable over the past seven years.
Why it matters
Understanding these enduring hot spots helps clarify whether Betelgeuse's surface is shaped by stable convection in polar regions or the gravitational influence of a companion star. These observations provide critical data as the star moves toward an eventual supernova.
The star, located 600 light-years away, spans 800 times the diameter of the Sun. Observations indicate a sub-millimeter photosphere temperature of 2300 K with radius deviations of up to 6 percent and clumpy gas extending to 2.5 times the stellar radius.
The players
Atacama Large Millimeter/submillimeter Array
An international radio telescope facility in the Atacama Desert that maps high-resolution stellar surfaces and cold dust.
Betelgeuse
A massive red supergiant star in the Orion constellation that is currently in a late stage of stellar evolution.
The details
The Atacama Large Millimeter/submillimeter Array — an interferometer using an array of 66 radio antennas to produce high-resolution images of celestial objects — captured these surface features. The heat likely originates from giant convective cells, which are massive bubbles of rising plasma that circulate hot gas from the star's interior to the surface. Research is ongoing to determine if these specific patches indicate permanent polar convection or external orbital interference.
Timeline
2019: Previous ALMA data collection for comparative analysis.
2020: Betelgeuse experienced a significant, well-documented dimming event.
October 2026: Publication of the new ALMA imaging results.
The Tech Race
This imaging effort follows a long-standing initiative by radio astronomy programs to map the chaotic surface dynamics of massive stars. It provides a baseline for future observations as the industry competes to capture the final stages of stellar evolution before a supernova.
While these observations do not change current astronomical models immediately, they provide the necessary data to better predict the future supernova event. Once the star eventually explodes, the resulting supernova will be visible from Earth during daylight hours.
The takeaway
These findings establish that surface activity on red supergiants can remain stable for nearly a decade, defying earlier assumptions of purely transient patterns. Observers should continue to track future ALMA reports for further analysis of the hot patch temperature variance.
Further reading
For more on ongoing stellar research, visit the Space section.
Source note: This article includes information reported by Tech Explorist.
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