This week Hal gives a preview of some of the wonders of the winter night sky.
Some of the most beautiful things in the night sky appear during the winter months. And they’re worth bundling up for, so southern Colorado and northern New Mexico listeners, grab a scarf and head outside, because beauty awaits.
One of the brightest and most beautiful stars in the sky, in fact there are only five brighter, is the winter star Capella. Rising in the northeast, it will be the brightest thing in that area of the sky. It glows with an orange-red-yellow color which is caused it to occasionally be confused with the planet Mars. But there’s a lot more going on there than meets the eye.
Capella is about 42 ly from Earth, not too far in astronomical terms. But when you look at Capella through a telescope you realize it’s a pretty interesting star. Because it’s not a star. Or more correctly, it’s not one star. Capella is made up of four different stars.
The two brightest, Capella A and Capella B, are each at least 10 times larger than our sun, and are locked in orbit around each other. But here’s where it gets even weirder – these giant stars orbit closer to each other, than the Earth is to our own Sun. In fact, they are a third closer to each other than we are to the Sun. And, they are speedy – they complete one full orbit around each other in only 104 days. One is 50 times brighter than our Sun and the other is 80 times brighter than our Sun, and they mostly burned through their nuclear fuel, so they are nearing the end of their lives. They’ll slowly turn in the red giant stars which will inevitably lead to them bumping into each other. It’s a crazy neighborhood
And did I mention that there are two more stars involved? While Capella A and B are only about 60 million miles apart, there are two more stars orbiting in the Capella system that orbit almost a full light year away from the two super bright stars. That’s about 3000 times farther than the Earth is from Pluto. So if you’re going to make that trip, pack two lunches – and a sweater.
If you’d like to take a closer look at Capella or any of the other wonderful and amazing things in the sky, please visit KRCC.org or CSASTRO.org for a link to information on our monthly meetings and our free public star parties!
This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!