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A new star can be seen in the night sky very soon – but not for long


Artists impression of T Cr B

T Cr B last exploded in 1946 (Picture: Nasa)

A ‘once in a lifetime opportunity’ is heading your way and all you have to do is look up.

Or it might be twice in a lifetime, if you’re lucky.

Sometime between now and September 2024, a ‘new’ star will appear in the sky – but only for a week.

That’s because around 3,000 light-years away, the star system T Coronae Borealis, or T Cr B, is about to explode. When it does, it will become visible to the naked eye here on Earth.

T Cr B last exploded in 1946, meaning some who saw it then could witness it again now – and many more will hopefully be around when it explodes again in another 80 or so years.

Astronomers predict that when it does erupt, it may be as bright as the North Star, Polaris.

As its brightness peaks, it should be visible to the naked eye for several days, and just over a week if you use binoculars before it dims again.

Astronomers at Nasa say the temporary new star will be located in the constellation Corona Borealis, or the Northern Crown, which is a small, semicircular arc near Bootes and Hercules.

Dr Daniel Brown, an associate professor in astronomy at Nottingham Trent University, said: ‘We are in for a treat, being granted a so-called new star in the skies.

The ‘new’ star will appear near Arcturus (Picture: Nasa)

‘T Coronae Borealis is actually not a single star but a binary, so two stars orbiting each other.

‘What makes this pair so special is that every so often it increases its brightness immensely to become easily visible to us.’

He said the more massive star in the pair is a white dwarf, which ‘can pack roughly the same mass as our Sun in a volume as large as Earth’.

Its companion, an ageing red giant, has expanded and is steadily dumping its material on to the white dwarf.

Jessica Lee, astronomer at Royal Observatory Greenwich said: ‘T Coronae Borealis is normally a very faint star with a magnitude of around 10, which means you’d need a pair of binoculars to see it.

‘However this star is actually a binary system, which means it’s a pair of stars orbiting each other. The system consists of a white dwarf star and a red giant star.

‘As the red giant star swells up and sheds its outer layers, the white dwarf star will pull this material onto itself. This material causes the star to heat up and the build up in heat eventually causes a “nova” or explosion on the surface of the star. This isn’t a supernova, so the whole star isn’t exploding or dying, but a temporary brightening of the star.’

Dr Brown said: ‘Every 80 years or so it [the white dwarf] gathers enough material so that it ignites in a thermonuclear explosion, boosting its brightness incredibly.

‘For T Coronae Borealis, the time is up for another such explosion, taking its brightness from 11mag – just about visible with binoculars in a dark …read more

Source:: Metro

      

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