'Once in a lifetime' cosmic explosion will create new star - here's how you can see it

Stargazers will soon be able to feast their eyes on once-in-a-lifetime celestial spectacular when a cosmic explosion will turn a distant star into one of the brightest objects in the night sky.

Between now and September, the binary star system known as T Corona Borealis (T CrB) will undergo an event known as a nova eruption.

As a result, it will be transformed from something roughly 100 times fainter than is possible to see with the naked eye to a brightness similar to Polaris, the Northern Star.

As a result people across the world, including in the UK, will be able to see a temporary new star in the sky.

NASA predicts this will happen anytime from now until September. 

Novae occur in binary systems in which a white dwarf – the remnant core of a former Sun-like star – co-orbits with a nearby stellar companion.

Research Fellow Mark Hollands, University of Warwick, said: “The ultra-dense white dwarf can steal material from the companion star in a process known as accretion, causing a layer of hydrogen to build up on the white dwarf surface. Once sufficient material has built up, this layer will reach a critical temperature, igniting hydrogen fusion.

“This powerful nuclear detonation ejects the gas from the white dwarf surface in a hot luminous shell. What we then see is the system becoming thousands of times brighter and is responsible for the observed nova.”

Most novae are unpredictable and seen only once - but there are 10 known repeating systems referred to as recurrent novae.

Of them is T CrB, which erupts about every 80 years, and which is by far the closest at a mere 3,000 light years away.

It is also the only one with a sufficient peak brightness to be visible to the naked eye in areas with moderate light pollution.

Mr Hollands added: “T CrB was first conclusively observed in outburst in 1866 by Irish astronomer John Birmingham, with the most recent nova seen in February 1946. Observations of T CrB in the months leading up to the 1946 eruption revealed a pronounced drop in brightness, indicating the explosion was imminent.

“Almost 80 years later, T CrB is now due for its next eruption event, and throughout February and March a dip in brightness was seen once more, signalling the fuse has been lit, and it is a matter of months before we witness the next nova.”

T CrB is much too dim to be seen with the naked eye at the moment, although it can be observed with a modest amateur telescope.

However, once the eruption gets underway, no special equipment will be required.

Mr Hollands said: “The best thing you can do now is to get familiar with the patch of sky around the constellation Corona Borealis, using a star chart or phone app. Once you get to know what stars are visible in that part of the sky, you’ll really appreciate the difference when one night in the next few months there is one extra member of the constellation.

“The nova will be visible to the naked eye for a few nights and reach a similar brightness to other stars in the Corona Borealis constellation, but if you miss that window, it’ll still be visible for a few weeks with a good pair of binoculars.

“At the University of Warwick we have a keen interest in white dwarfs in interacting binary systems. Weather permitting, we hope to observe this once in a lifetime display using the new Marsh Observatory on the Warwick campus.”

While our Sun will evolve into a white dwarf in around 5 to 6 billion years time, it does not have a stellar companion to accrete material from, and so will not undergo nova eruptions.

Since T CrB is around 3000 light years away, the nova outburst is only now that the light is reaching us. In that time, T CrB will have undergone 35-40 more outbursts with all of their light signals on the way.