The North Star, Polaris, is a Cepheid variable - that is, a yellow supergiant whose luminosity varies periodically on a timescale of several days. Now, it seems Polaris has another, much longer timescale of variability. Interestingly, modern astronomical cameras are too sensitive to study such bright stars. The astronomers who discovered the long-timescale variability had to resort to older technology!
Posted on: Wed, 29 Jan 2014 17:14:03 +0000
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