Runaway star races
DR EMILY BALDWIN
Posted: 26 January 2011
NASA's Wide-field Infrared Survey Explorer, WISE, has photographed a speeding star as it hurtles through space at nearly 90,000 kilometres per hour.
The star, known as zeta Ophiuchi, is some twenty times the mass of our own Sun, but astronomers think it must have once orbited around an even heftier star that exploded in a dramatic supernova event at the end of its life. The explosion kicked zeta Ophiuchi onto its new path at a breakneck speed of 24 kilometres per second (approximately 87,000 kilometres per hour).
The star, seen here as a blue dot inside the yellow arc of the bow shock, is racing through space at 24 kilometres per second towards the top left of this image. Image: NASA/JPL-Caltech/UCLA.
As it races through space, its powerful winds push interstellar gas and dust out of its way to create an arc of compressed material in front of it, called a bow shock. This shock wave is so compressed that it glows in infrared light, which WISE is able to detect. Radiation streaming out of the star is heating the dust in the immediate vicinity, giving it a red glow, while further away the clouds of dust and gas remain undisturbed. In visible light only the star can be seen.
Zeta Ophiuchi is burning through its lifespan too – it is already halfway through its short eight million year life. In comparison, our Sun is only halfway through its 10 billion year life expectancy. While the Sun will eventually swell into a red giant before shrinking into a white dwarf, zeta Ophiuchi will go out with a bang, exploding in a supernova just like its long-lost companion.
The Universe under one roof. European AstroFest returns to London on February 7 & 8, 2014. The UK's favourite astronomy conference and exhibition. Visit the official website site for more details.
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