Keeping in the loop

I was rather gratified the other day, to learn that I’m not boring for being a fan of Orion. Apparently, several other people pick Orion as their favourite constellation, ever vigilant in the skies from almost anywhere on the planet. Much more than a familiar grouping of stars, however, Orion is a quite interesting place.

Orion, you see, is home to the Orion molecular cloud complex – the closest star forming region to us here on Earth. Even as you read this, the giant molecular clouds in Orion are busily collapsing into bright and shiny new stars.

Perhaps the most striking feature of the Orion molecular clouds, however, is known as Barnard’s Loop, shown here in this gorgeous image. Taken by Spanish-born astrophotographer Rogelio Bernal Andreo (, this is quite simply the best image of Orion’s dusty shroud I’ve ever seen!

Barnard’s Loop is the huge arc you can see to the right of the image. Glowing in red H-α light from hot excited hydrogen atoms, the Loop spans around 300 light years from side to side. The hot newborn stars in the Orion nebula are thought to be what’s causing the red glow right now, but the Loop was probably originally born in a supernova explosion around 2 million years ago. The last remains of what would have once been one of the grandest supernova remnants in the night sky. Despite being so vast, however, it’s an extremely faint object. Unless you have excellent eyesight and suitably dark skies to view it from, you won’t be able to see it with the naked eye.

Incidentally, there’s a little more history behind that supernova too.  Here and there, astronomers find runaway stars. Stars travelling at high speeds, having been given an almighty kick at some point in their past. Three such runaway stars near us are AE Aurigae, Mu Columbae, and 53 Arietis. Once upon a time, these speeding stars were probably all part of a multiple star system, together with another more massive companion keeping them all in check. It was that massive star which exploded to form Barnard’s loop, and the punch from the supernova explosion was what flung the three other stars away at high speeds.

Life is evidently turbulent sometimes, even in our quiet little neighbourhood here in the Milky Way galaxy.

For more fantastic astrophotography to amaze you, have a look at Deep Sky Colors, Rogelio Bernal Andreo’s fantastic online gallery. I assure you, you won’t be disappointed!

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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4 Responses to Keeping in the loop

  1. On the topic of supernovas, the prospects for Betelgeuse going up (or having gone up) are interesting. The first naked-eye supernova of the millennium …

    • Pseudonym says:

      I really don’t believe it’s going to explode (or have been exploded about 600 years ago due to its distance) this millenium. It will be a great show though.

      Out of the topic: Have you guys heard about two bright comets are coming next year? Well, they say comets are pretty unpredictable, but if they survive it will be a great show!

      • invaderxan says:

        While I’m not exactly holding my breath for it, in fairness there’s no reason to believe either way. All we can do is watch and appreciate it while it still exists in the night sky.

        And no, I hadn’t heard about those comets. I’ll have to try and find out more. Thanks for the tip!

    • invaderxan says:

      Indeed… Especially as no one really knows what happens to a star as it goes supernova. What telltale signs and changes might occur. Though no one has any way of predicting when Betelgeuse might explode, with it being so close there’s bound to be someone watching when it does!

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