Betelgeuse
The scorching-hot surface of the red supergiant is tricking telescopes
Recent observations of Betelgeuse, a star located in Orion, have created a mystery about the red supergiant. They suggest that it’s spinning much faster than a star its size should be able to. A team from the Max Planck Institute for Astrophysics, led by PhD student Jing-Ze Ma, may have an explanation for why Betelgeuse appears to be spinning so utterly fast – perhaps it’s an illusion created by the star’s violently boiling surface.
Ma and his colleagues think the star’s bubbling surface could be mistaken for rotation, even by the most advanced telescopes. This mistake could lead to observers believing that Betelgeuse, which is located around 642.5 light years from Earth, appears to be rotating faster than should be possible for a star of such enormity. “For most people, stars are just glowing dots in the sky. Our results highlight that stars like Betelgeuse have such drastic boiling motions on the surface that we can see those motions in action in telescopes,” Ma said.
Betelgeuse is an infamous red supergiant star that recently made headlines when its dimming led scientists to speculate that it may be about to explode. “Most stars are just tiny points of light in the night sky. Betelgeuse is so incredibly large and nearby that with the very best telescopes it’s one of the very few stars where we actually observe and study its boiling surface,” Selma de Mink, research co-author and scientific director at the Max Planck Institute for Astrophysics, said.
Betelgeuse is one of the brightest stars in the Northern Hemisphere, meaning it’s well studied, but as observations of its dimming show, that doesn’t mean it isn’t capable of delivering surprises. With a diameter greater than a billion kilometres (620 million miles), Betelgeuse is over 1,000 times larger than the Sun, making it one of the largest stars in the known universe. Recent observations of Betelgeuse, particularly those made with the Atacama Large Millimeter/submillimeter Array (ALMA) located in Northern Chile, showed that Betelgeuse is rotating at around 18,024 kilometres (11,200 miles) per hour.
An investigation with ALMA, an observatory composed of 66 radio antennae that together form a single telescope, revealed that while half of Betelgeuse appears to be approaching Earth, the other appears to be receding. It was this so-called ‘dipolar radial velocity map’ on the outer layer of Betelgeuse that scientists interpreted as rapid rotation. But this interpretation hinges on Betelgeuse being considered a perfectly round sphere – and this isn’t the case. The surface of the red supergiant star is turbulent with boiling bubbles, and some of those bubbles are as large as Earth’s entire orbit around the Sun. These bubbl
