Betelgeuse, one of the brightest stars visible to the naked eye, has shrunk in diameter by more than 15 percent since 1993.
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In 1921, Betelgeuse became the first star for which astronomers measured a size. Over the years, different interferometers, observing Betelgeuse over a wide range of wavelengths, have recorded diameters for the star that disagree with each other by as much as 30 percent. That’s not surprising because stars often look considerably bigger or smaller at different wavelengths. But the star hasn’t previously been found to vary significantly in size at any one wavelength, Townes says.
As hefty as 15 suns, Betelgeuse is nearing the end of its life and could soon go supernova. Continued close monitoring of Betelgeuse could lead to a better understanding of the evolution of massive stars near the end of their lifetime.
via Jorn Barger