Dschubba "... one star out of four"

Jun 27, 2016

    

Scorpion rising - May 2016
Credit M. Procell

This week Hal discusses Dschubba, a star (or 4) located in the head of Scorpius the Scorpion.

There are 88 constellations in the night sky, counting those in both the northern and southern hemispheres. Many of them look nothing like their names. Indeed, some of them are quite a stretch - I’m looking at you Ophiuchus. Sure, you look like a snake bearer.

But there are some that really do look like their namesake, and Scorpius the scorpion is one of those. With stars that seem to line up to make a body with a curved tail and stinger, and other stars that appear to line up to form the head and pincers, Scorpius looks like, well, a scorpion, and you can see it all summer in the southern Colorado sky.

But there’s something strange going on in the head of the scorpion. The middle of three stars forming the head, Dschubba, has been giving astronomers problems because of its weird behavior.

Dschubba was, for many, many years, a very ordinary appearing star at a very ordinary appearing brightness. But in the year 2000, Dschubba started getting brighter. It seemed to be turning itself into a very  different kind of a star that was before.

Its brightness peaked in 2004, and then it started to get dimmer. But it ultimately stayed a little brighter than it had been before. So what the heck is going on out there?

It appears that Dschubba is not actually a star. It’s likely a group of four stars, all orbiting and interacting dramatically with each other, as they get closer and farther away. It looks like the two biggest stars may have gotten very close together in 2000, which may have triggered the brightening. The biggest of the four stars is five times bigger than our Sun, and is 14,000 times brighter. Sometime in the next million years or so, astronomers think this star will either become a calm and quiet white dwarf, or will explode as a supernova. If the latter, Scorpius will have quite a headache.

If you’d like to take a closer look at Dschubba, or any of the other 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! 

This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!