A 10-year-old Canadian girl has become the youngest person ever to discover a supernova, or exploding star, according to the Royal Astronomical Society of Canada.

Eagle-eyed Kathryn Aurora Gray, from Fredericton in the eastern province of New Brunswick, made the rare find on Sunday as she combed dozens of telescopic images of star fields in far-away galaxies.

"The RASC is pleased to announce the discovery of a supernova by a 10-year-old amateur astronomer -- the youngest person ever to have made such a discovery," the society said in a statement.

On spotting Supernova 2010lt in the constellation of Camelopardalis in a galaxy 240 light-years from Earth, Gray immediately told her delighted amateur astronomer father Paul.

The find was then verified by two US-based amateur astronomers before being reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams.

Supernovae are massive stars that run out of fuel, collapse under the weight of their own gravity and become an ultra-dense object known as a neutron star.

They then send out a shockwave that rips the star apart and leaves a sizzling cauldron of radiation.

These colossal events are among the most thrilling phenomena for astronomers and are detected when the high-energy explosion creates a dramatic flare that eventually fades.