This bright star in our night sky has a companion
What's the story
Astronomers have confirmed the existence of a long-suspected companion star to Betelgeuse, one of the brightest stars in our night sky. The discovery was made by a team led by Dr. Steve Howell from NASA's Ames Research Center. They used a speckle imager known as 'Alopeke' mounted on the Gemini North telescope, part of the International Gemini Observatory.
Detection
Detection made possible by Gemini North's 8.1-meter mirror
The detection of Betelgeuse's faint companion was made possible by the high resolution and light-collecting power of Gemini North's 8.1-meter mirror. The team analyzed the light from the companion star to determine its characteristics, which were published in The Astrophysical Journal Letters. They found that it is six magnitudes fainter than Betelgeuse in optical wavelengths, and has an estimated mass of around 1.5 times that of our Sun.
Stellar profile
A look at the star type
The companion star is possibly an A- or B-type pre-main-sequence star, a hot, young, and blue-white body that has not yet started hydrogen burning in its core. It is located at a distance of about four times the Earth-Sun distance from Betelgeuse's surface. This discovery marks the first time a close-in stellar companion has been detected orbiting a supergiant star.
Fate
It will die within 10,000 years
The companion star shall have a short lifespan due to strong tidal forces that will pull it into Betelgeuse, leading to its demise within 10,000 years. This discovery also sheds light on why similar red supergiant stars may exhibit periodic brightness changes over many years.