This event will make T CrB, currently too faint to see with the naked eye, as bright as the Northern Star (Polaris), offering a temporary new star visible to much of the world, including the UK.

Understanding Novae
Novae occur in binary systems where a white dwarf co-orbits with a stellar companion. Research Fellow Mark Hollands of the University of Warwick explained: "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."

T CrB is a recurrent nova, one of ten known systems that erupt periodically. It is the closest such system at 3000 light years away and the only one bright enough to be seen with the naked eye in areas with moderate light pollution.

"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," added Hollands.

How to Observe T CrB
Currently too dim to be seen without a telescope, T CrB will become visible to the naked eye once the eruption occurs, even in moderately light-polluted areas.

"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," said Hollands.

"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."

Related Links
University of Warwick
Stellar Chemistry, The Universe And All Within It