Fast-living star creates shockwaves

A space telescope has photographed the dramatic shockwaves caused by a runaway star ripping through the galaxy like a bullet. The massive star, bright enough to be easily spotted by backyard stargazers, is racing at 54,000 mph through a cloud of dust and gas.

Zeta Ophiuchi imaged by WISE (NASA)

NASA used an orbiting observatory called WISE – Wide-field Infrared Survey Explorer – that sees the sky in infrared light.

It recorded a brilliant bow shock resembling a yellow arc as its powerful stellar winds push the gas and dust out of the way.

Astronomers believe the star, labelled Zeta in the constellation of Ophiuchus the serpent-bearer, once revolved around another star. But its companion exploded as a violent supernova, flinging Zeta out into deep space.

Zeta Ophiuchi is a very massive hot blue star that is 65,000 times brighter than our own Sun and 20 times its size. It lies 458 light years away and would appear brighter in the night sky if it were not shrouded by the gas and dust (it is around magnitude 2.5 on the astronomers’ scale).

But it is a mayfly among stars because it is already halfway through its brief eight million year life, compared to the 10 billion years that the Sun is expected to survive. Like its long-lost companion, it will then blow itself to pieces in a supernova blast too.

To the sides of the image and in the background are relatively calm clouds of dust, which appear green and wispy. But close to Zeta Ophiuchi, they are brighter and redder, because the extreme amounts of ultraviolet radiation emitted by the star are heating the cloud, causing it to glow more brightly in the infrared.

Zeta is not the first runaway star we have reported on – one has been discovered fleeing a giant black hole.

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available. Check out our monthly sky guide too!

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