Betelgeuse, Betelgeuse! The red supergiant that marks Orion’s left shoulder may have a tiny, unseen companion.
Two independent studies found evidence of a star about the same mass as the sun, orbiting Betelgeuse about once every 2,100 days.
“It was very surprising,” says astrophysicist Morgan MacLeod of the Harvard & Smithsonian Center for Astrophysics in Cambridge, Mass. If the star is real, “it’s kind of hidden right there in plain sight.”
MacLeod and colleagues linked a six-year cycle of Betelgeuse brightening and dimming to a companion star tweaking its orbit, in a paper submitted to arXiv.org September 17. MacLeod examined global, historical measurements dating back to 1896.