The Biggest Belt in the Universe
This is Orion’s belt, in the constellation Orion, the hunter. It’s what’s called an asterism, which is basically a smaller group of stars within a constellation (fun fact, if you ever want to blow someone’s mind, inform them that the Big Dipper is not actually a constellation. Really, look it up.).
This photo, aside from being stunning in its detail, is a wonderful example of how the distance between the stars is hidden to the naked eye. Each of the three stars, from left to right are Alnitak, Alnilam, and Mintaka (or, for the Greek lovers out there: Zeta, Epsilon, and Delta Orionis). These stars appear in the sky, and in this photo to be in a straight line, and very close together. But you may have already guessed that this is not the case. And you’d be right! So smart, readers. I like you.
Yes, they’re all very far apart from one another. And though to the naked eye they all appear to be the same distance from Earth, that is also untrue. What’s more, they all have interesting stories to tell when you consider them individually. Let’s take a look.
736 light years distant, this star is actually part of a triple system of stars; three stars locked in orbit around a common center of mass (this is actually the norm when you get right down to it. Single stars like our Sun are rarer indeed). The star we see is a blue supergiant about 28 times the mass of the sun, and about 20 suns wide.
The most distant star in the belt, at 1340 light years’ distance, Alnilam is also the most curious, an the most active. It’s another blue supergiant, smaller than Alnitak, about the size of 24 suns, but a lot of its’ mass has gone away from it. You see, Alnilam is a bit of a speed demon. It rotates at about 91 km/second, and produces a stellar wind that can blow in excess 2000 km/s. That means it’s constantly losing a lot of mass in the form of molecular discharges. Where does this material go? It has formed in a nebula called NGC 1990: a beautiful blue cloud that surrounds the star, and is the birthplace of the stars of the future.
Finally, we have Mintaka. Its distance lies in the middle, at 915 light years. It too is not a single star, but part of a binary. The one we see is a giant about 20 times the size of the sun. Not much else about this star is incredibly interesting, but it’s the only one on this list to have a U.S. battleship named after it, so that’s something, right?
But Wait, There’s More: The Flame Nebula
You may also have noticed the red cloud in the left of this picture, and it’s a good thing if you did because it’s a very important place. This is the Flame Nebula, and just like the one mentioned above, this is a place where large collections of gas and dust clump together, ignite, and give birth to the stars. I recommend finding another picture of this thing, because this one doesn’t quite do its beauty justice.
So you may have though that two nebulae in one constellation is a lot. Well, it is, but there’s more to this story. Orion is literally crawling with the things. In fact, I may just have to do a whole post on that…
But for now, thanks as always for reading. Again as always, any questions, concerns or hate mail can be directed to the Ask box.
Nobody reading this article could see where i pulled my rp troll’s name. Not at all