Astronomy: Previously overlooked star in Betelgeuse cause of eclipses?
Researchers have long been trying to determine when Betelgeuse will explode on the basis of regular eclipses. Now there is a completely new approach.
Artistic representation of Betelgeuse and "Betelbuddy"
(Image: Lucy Reading-Ikkanda/Simons Foundation)
The red giant star Betelgeuse is not on the verge of a huge explosion after all; instead, fluctuations in brightness interpreted in this way are probably due to a companion. At least that is the theory of a US research team, which contradicts a paper published a year ago. The team now claims that they have ruled out all of the star's own sources that could explain the periodic fluctuations in brightness: "The only hypothesis that seems to fit is that Betelgeuse has a companion", says astrophysicist and first author Jared Goldberg. Observations could confirm this in just a month and a half.
"Impossible to explain" without a companion
In their analysis, Goldberg's team focused on the brightness cycles based on which researchers are trying to date the expected end of Betelgeuse. This is because the bright star periodically becomes brighter and dimmer, with two identified pulses lasting 420 days and 2200 days. If the shorter one were the central rhythm, the final supernova could be expected in just a few decades; otherwise we would have to wait another 10,000 to 100,000 years. While a research team declared a year ago that the shorter one is the central pulse, Goldberg's team now believes that it is a secondary "heartbeat". The approximately six-year pulse would then have to originate from an external source.
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(Image:Â Lucy Reading-Ikkanda/Simons Foundation)
Based on the observational data and advanced computer simulations, the group has determined that the most likely explanation for the long pulse is a second star. It could have about twice the mass of our sun and regularly remove dust from the vicinity of Betelgeuse, which would make it appear brighter. Goldberg calls the proposed star "Betelbuddy" and says, "If Betelbuddy doesn't exist, then it means something much stranger is going on – something we can't possibly explain with our understanding of physics". The companion could possibly be visible to telescopes as early as December 6, and the team plans to check it out. The research has been accepted for publication in The Astrophysical Journal.
Betelgeuse is the shoulder star of the constellation Orion and is normally one of the brightest at night sky. However, it has recently caused quite a stir with a massive dimming and then a brightening. Researchers agree that it has reached the end of its life, but the final supernova is not actually expected in our lifetime. A year ago, however, it was said that exactly that was possible. However, a group led by astronomer László Molnár, who was also involved in the new work, contradicted this at the time. If a previously overlooked star is indeed discovered at Betelgeuse, this would show that there is room for significant discoveries even after centuries of research.
(mho)
