Polaris’s Pulsation

By Michael on July 24, 2008 at 11:30 pm | In Blog Posts |

(For the grammar nerds, my understanding is, if a proper name ends with an ’s’ you still put an apostrophe ’s’ after it. The only case where you put only the apostrophe after the ’s’ is when the word is plural e.g. “our clients’ best interests”.)

I was going to write up a post about Polaris aka the North Star but Simostronomy beat me to it. In a nutshell, Polaris is a Cepheid variable star with a very low amplitude, so the brightness does not change very much. A new paper points out that the amplitude is increasing and Mike does a very nice job of explaining it.

One thing I like to do when under a dark sky like at a camp fire or floating in a boat is ask people to point at the North Star. Most people look for the brightest star and will point to it without giving any thought to the direction to which they are pointing! The North Star is due north of you everywhere you can see it and it is not the brightest star, by far. Its altitude above the horizon is equal to your latitude so here in Minneapolis it is 45 degrees above the horizon.

Besides it’s important (and temporary) role as the North Star, Polaris is one of the brighter Cephied stars and it appears to be going through changes in human time scales, which is always fun for astronomers.

So, thanks Mike! Now instead of blogging I can go play some Age of Conan.