NASA's Hubble Scope Helps Resolve An Enduring Mystery: Why Does Betelgeuse Brighten And Dim, About Every 2,100 Days?

The companion star, only a tiny fraction the size of the monster it closely orbits. . . has been dubbed Siwarha by the team who "discovered" her orbit.

The term derives from ancient Arabic -- and translates as "her bracelet". Especially fitting, since she carves a space-time ring -- around the "wrist" of the massive Betelgeuse.

Do read go it all -- as this always fires my imagination: the moment of revealing, of that new "undiscovered country" (per NASA):

. . .The team detected Siwarha’s wake by carefully tracking changes in the star’s light over nearly eight years. These changes show the effects of the previously unconfirmed companion as it plows through the outer atmosphere of Betelgeuse. This discovery resolves one of the biggest mysteries about the giant star, helping scientists to explain how it behaves and evolves while opening new doors to understanding other massive stars nearing the end of their lives.

Located roughly 650 light-years away from Earth in the constellation Orion, Betelgeuse is a red supergiant star so large that more than 400 million Suns could fit inside. Because of its enormous size and proximity, Betelgeuse is one of the few stars whose surface and surrounding atmosphere can be directly observed by astronomers, making it an important and accessible laboratory for studying how giant stars age, lose mass, and eventually explode as supernovae. . . .

Using NASA’s Hubble and ground-based telescopes at the Fred Lawrence Whipple Observatory and Roque de Los Muchachos Observatory, the team was able to see a pattern of changes in Betelgeuse, which provided clear evidence of a long-suspected companion star and its impact on the red supergiant’s outer atmosphere. Those include changes in the star’s spectrum, or the specific colors of light given off by different elements, and the speed and direction of gases in the outer atmosphere due to a trail of denser material, or wake. This trail appears just after the companion crosses in front of Betelgeuse every six years, or about 2,100 days, confirming theoretical models. . . .

The scale of these events is just. . . staggering. Most of our frames of reference are sub-nanometer, by comparison. But what a sight it would be, if we could witness it, from about five or so light years off. Whoosh -- a safe distance, so we wouldn't burn up -- but it would still fill most of our [at this point mythical] spacecraft's forward viewing window.

Very cool -- and in the masthead below, our Sun would be less than 1/600,000^th of a pixel in size!

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