Science
ALMA images reveal long-lived hotspots on Betelgeuse's surface
New observations of the nearby red supergiant show temperature anomalies that have persisted far longer than predicted by current convective models.
The short version
- New observations from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal that the red supergiant star Betelgeuse has an irregular, non-spherical surface and an average atmospheric temperature of 2300 K.
- A prominent northeastern hotspot has surprisingly persisted in nearly the same location and intensity for at least seven years, defying existing convective models that predict shorter lifetimes for such structures.
- Astronomers plan to continue high-resolution monitoring to determine if these hotspots remain fixed and how they affect the star's atmospheric structure as it nears a supernova explosion.
Key facts
- Using ALMA's longest-baseline configuration in 2023, astronomers imaged the surface of Betelgeuse at a resolution of seven milliarcseconds.[Hacker News]
- The observations revealed two hot regions to the northeast and southwest of the stellar disk, with the brightest hotspot being roughly 800 K hotter than the surrounding 2300 K atmosphere.[Hacker News]
- A comparison between 2023 and 2015 ALMA data showed that the northeastern hotspot has persisted in nearly the same location and intensity for at least seven years.[Hacker News]
- ALMA measured variations of up to about six percent in the star's apparent radius, indicating a highly non-spherical surface.[Hacker News]
- Betelgeuse is located approximately 600 light-years from Earth and has a radius roughly 800 times larger than the Sun.[Hacker News]
What remains uncertain
- While researchers note the alignment of the long-lived hotspots is intriguing given recent evidence of a close companion star to Betelgeuse, the current observations do not establish a direct connection.[Hacker News]