Betelgeuse in the News Again

 So, it turns out that the red giant Betelgeuse was still in main sequence only two thousand years ago. Well, plus the light years it is away.

We know this from observations made by Chinese and Roman astronomers in about 100 B.C. In fact, the Chinese court astronomer at the time, Sima Qian, used Betelgeuse as an example of a yellow star. An example. This means that he considered it to be the best yellow star out there.

In about 1AD, Hyginus also described the star as yellow-orange, about the color of Saturn.

We also know that it was red by the 16th century, and perhaps we'll find observations that pinpoint when the change became visible.

(My initial reaction was "Did it change at about ya know...a certain time...and was Betelgeuse the Star of Bethlehem, but it looks like the Roman observations make it too late")

I'm actually wondering if it didn't turn visibly red until the 16th century. Surely a known yellow star turning red would have been marked down as an omen by somebody. Even if it wasn't in Europe, the Chinese, Arabs or even the Maya would have made note of it. Just a thought.