Astronomers may have uncovered the cause of Betelgeuse's strange dimming
Researchers have found evidence that a companion star may influence Betelgeuse, explaining why the latter star's brightness changes over time.
NASA/ESA/Elizabeth Wheatley/STScI (artwork); Andrea Dupree/CfA (science)
Astronomers may have finally solved one of the strangest mysteries of our night skies: why Betelgeuse, a massive star in the constellation Orion, appears to dim and brighten as if it were being controlled by a celestial dimmer.
Using the Hubble Space Telescope and ground-based observatories, scientists observed Betelgeuse for nearly eight years and discovered that patterns in the star's light indicate that the trail of another, unseen star is passing through its atmosphere.
“It's a little like a boat moving on water. The companion star creates a ripple effect in Betelgeuse's atmosphere that we can actually see in the data,” said Andrea Dupree, an astronomer at the Center for Astrophysics | Harvard and Smithsonian Institutions and Lead Author preprint paper about the conclusion, which will be published in Astrophysical JournalV statement.
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Another star seems to pass in front of Betelgeuse every six years or so. If the results are confirmed by follow-up observations, they will help explain why Betelgeuse, a bright nearby star that could fit 400 million suns inside, periodically appears as if it is about to disappear before our eyes. That's exactly what happened in 2020, when Betelgeuse appeared so weak that it sparked rumors that it might be about to explode. supernova. (Astronomers didn't think such a cataclysm was inevitable at all. But they were very confused.)
Scientists had predicted the existence of a companion star, called Sivarha, earlier. But there was no evidence, Dupree said in a recent statement.
“With this new direct evidence, Betelgeuse gives us a front-row seat to watching how the giant star changes over time,” she said. “Finding the signature of its companion means we can now understand how such stars evolve, lose material and eventually explode as supernovae.”
The research was presented Monday at the annual meeting of the American Astronomical Society.
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