'Champagne Supernova' breaks astronomical rules

A massive supernova, bigger than previously believed possible, could have astronomers rethinking how stars explode and even how far away stars and galaxies are.

A team of astronomers, led by researchers at the University of Toronto, found the supernova using the Canada-France-Hawaii telescope and the Keck telescope, both on Muana Kea in Hawaii.

University of Toronto researcher Andy Howell identified the supernova, called SNLS-03C3bb. Another astronomer has dubbed it the "Champagne Supernova" because its discovery is cause for celebration.

The supernova is a Type Ia, a nuclear explosion in a white dwarf star that has gathered up matter from another nearby star.

The current understanding is that Type Ia supernovas explode when the white dwarf's mass approaches 1.4 times the mass of the sun, called the Chandrasekhar limit.

This limit was discovered by Indian physicist and Nobel laureate Subrahmanyan Chandrasekhar in 1930.

Because of this limit, Type Ia supernovas usually have about the same brightness and are considered a "standard candle" for measuring distances in the universe. Years of astronomical research and mapping are based on this limit.

However, this supernova occurred when the white dwarf reached about two solar masses.

'Nature has found a way'

"It should not be possible to break this limit, but nature has found a way," Howell said in a statement.

The research appears in Thursday's issue of the journal Nature.

In a separate article on the research, University of Oklahoma astronomer David Branch called the discovery a "Champagne Supernova" because it could lead to new insights into how stars explode.

The study's co-author, Mark Sullivan of the University of Toronto, dubbed it a "rogue supernova."

The teamthat found the supernova has two theories about how the white dwarf got so big before it exploded.

One is that the star was spinning at such a high speed that gravity couldn't pull it in and crush it at the normal Chandrasekhar limit.

Another theory is that the observed supernova is the result of two white dwarfs merging and that the two stars together exceeded the limit only briefly before exploding.