Red Supergiant Star Betelgeuse May Have Eaten Sun-Sized Companion

A new study says that giant red star Betelgeuse may have eaten its companion star.

Space.com reported that the "red supergiant" Betelgeuse, which makes up the shoulder of the constellation Orion, may have eaten its companion star that almost had the same size as the Sun. The cannibal star reportedly has a mass 15 to 25 times more than the Sun and measures about 1.4 billion kilometers wide -- making it 1,000 times bigger than the Solar System's main star.

In fact, when one replaces the Sun with Betelgeuse, it would occupy an enormous space up to the asteroid belt, which is located just past Mars. However, the supergiant is located 640 lightyears away from the Sun, which explains why it looks smaller in the naked eye.

Since it is a supergiant star, scientists would expect it to spin slowly as rotation rate decreases when the size increases. But Betelgeuse has a unique case. It rotates at an astounding speed of 33,500 mph (53,900 km/h), which got scientists wondering how it happened.

"We cannot account for the rotation of Betelgeuse," said study's lead author J. Craig Wheeler, an astronomer at the University of Texas at Austin in a statement. "It's spinning 150 times faster than any plausible single star just rotating and doing its thing."

This led his team to speculations that Betelgeuse may have eaten a smaller companion star, which had transferred its orbit's angular momentum to the bigger star.

"Suppose Betelgeuse had a companion when it was first born? And let's just suppose it is orbiting around Betelgeuse at an orbit about the size that Betelgeuse is now. And then Betelgeuse turns into a red supergiant and absorbs it - swallows it," he said.

This study was published recently in the journal Monthly Notices of the Royal Astronomical Society.