For one of the brightest stars in the sky, Betelgeuse still has some surprises up its sleeve. We’ve known for a couple of years it’s surrounded by a cloud of gas, but new observations show that nebula is far larger than previously thought!
[Click to enorionate.]
This new image is care of the Very Large Telescope, and shows a very deep and very high-resolution shot of Betelgeuse in the infrared. The inner black circle is the 2009 shot of the star and its surrounding gas — what we knew about before — and the big image shows all the gas around it just discovered. At the very center is a red circle indicating the actual size of Betelgeuse on this scale — it’s a red supergiant, and nearly two billion kilometers in diameter.
This structure is actually a wind of material blown off of the star itself. The exact mechanism behind this is unclear, though. Red supergiants are so big that gravity on their "surface" (they don’t really have a surface; they just kinda fade away into space) is very weak, and they can barely hold on to ...
Full story at http://blogs.discovermagazine.com/badastronomy/2011/06/23/betelgeuses-sandy-belch/
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