Looking Up: A Goat Tail Tale

Oct 2, 2017

Credit By Firkin / Creative Commons Open Clipart

This week on Looking Up Hal tells the tale of Scheddie, a dying star in the constellation Capricornus.

Some people are known by a single name, like Cher, just as some stars are known by a single name, like Polaris or Betelgeuse. But most of us have more than one name, and there is a star in the Southern Colorado sky right now with at least three names. 

Part of the constellation Capricornus is the star Delta Capricorni, also known as Deneb Algedi, and lastly, Scheddi, meaning “tail of the goat.” And maybe it’s a good thing it has three names, because as it turns out, it isn’t even one star.

Rather, it is actually FOUR stars, all spinning around each other. The biggest one is about 8 times brighter than our Sun. And it has a little companion star that orbits around it – get this – about once every day. That’s a very close orbit, and as the little guy passes in front of its big brother, the brighter star actually dims a wee bit as the dimmer, smaller star passes in front. Your eye can actually see the difference in brightness during what is technically an eclipse. The other two stars of the system orbit quite a bit farther out, and are much dimmer. And things are getting tense out there – the primary star is apparently very near the end of its life span, as it is running out of hydrogen to fuse. There are lots of metals in its core, and it has started pulsating, likely a prelude to its stellar death. So wave goodbye to Scheddi, it’s only got a few million years left.

If you’d like to take a closer look at Scheddi or any of the wonderful and amazing things in the sky, please visit csastro.org for a link to information on our monthly meetings and our free public star parties.