Betelgeuse may be a well-known and often-studied stellar object, but that doesn’t mean astronomers aren’t capable of capturing this doomed star in a completely new light.
A team of scientists examined the doomed red supergiant star with the Atacama Large Millimeter/submillimeter Array (ALMA), gaining new, highly detailed insights into its turbulent surface.
Betelgeuse, located around 600 light-years away, captured the public’s attention a few years ago when the rapid and dramatic dimming of the infamous highly evolved star led some scientists to hypothesize that it was about to explode in a spectacular supernova. That hasn’t happened, and scientists are now less convinced that this explosion is immediately imminent, but Betelgeuse remains the subject of intense scientific scrutiny.
“Its eventual fate as a supernova makes it fascinating to know what it actually looks like now,” team leader Bill Dent, an astronomer at the European Southern Observatory (ESO), said in a statement.
The newly released ALMA images of Betelgeuse, captured in 2023, show bright hotspots on the star’s surface and an almost corrugated texture arising from vast amounts of plasma shifting through the star, which has around 20 times the mass of our sun, but is puffed out to around 800 times the size of our star.
The observations show the red supergiant has an atmosphere with a temperature of around 3,680 degrees Fahrenheit (2,030 degrees Celsius), but possesses at least two regions even hotter than this. One of these areas is 980 degrees Fahrenheit (530 degrees Celsius) hotter than the plasma surrounding it.
The uneven nature seen by ALMA is likely the result of massive convective movements in the star, hot plasma rising through the star and generating shockwaves that erupt in the star’s atmosphere, creating bright and hot regions.
The familiarity of Betelgeuse to astronomers doesn’t mean the star isn’t capable of delivering surprises too. When the team compared images collected in 2023 to observations from 2015, they were surprised to see a hotspot in the northeast of the stellar disk has persisted for at least seven years, that is much longer than predicted by current stellar models.
The orientation of the hotspots of Betelgeuse also added support to the idea that the red supergiant star is orbited by an elusive companion star.
Astronomers will continue to monitor the hotspots of Betelgeuse with ALMA to determine how fixed they are and how their evolution relates to things like mass loss, and the structure of the star’s atmosphere.
That investigation will likely continue until Betelgeuse finally ends its life in a supernova explosion.
The team’s research has been accepted for publication in the journal Astronomy & Astrophysics and is available on the paper repository site arXiv.