'Champagne supernova' challenges understanding of how supernovae work

Sep 20, 2006
'Champagne supernova' challenges understanding of how supernovae work
The supernova SNLS-03D3bb was discovered on April 24, 2003 in a small, young, star-forming galaxy, a satellite of the larger galaxy in this picture. Image on the left is before maximum brightness; at maximum brightness (right), the supernova was much brighter than its host.

An international team of astronomers led by a group at the University of Toronto has discovered a supernova more massive than previously believed possible. This has experts rethinking our basic understanding of how stars explode as supernovae, according to a paper to be published in Nature on September 21.

University of Toronto postdoctoral researcher Andy Howell, lead author of the study, identified a Type Ia supernova named SNLS-03D3bb in a distant galaxy 4 billion light years away that originated from a dense evolved star, termed a 'white dwarf,' whose mass is far larger than any previous example. Type Ia supernovae are thermonuclear explosions that destroy carbon-oxygen white dwarf stars that have accreted matter from a companion star.

Researchers say SNLS-03D3bb’s “obesity” has opened up a Pandora’s box on the current understanding of Type Ia supernovae and how well they can be used for precision cosmology.

Current understanding is that Type Ia supernova explosions occur when the mass of a white dwarf approaches 1.4 solar masses, or the Chandrasekhar limit. This important limit was calculated by Nobel laureate Subrahmanyan Chandrasekhar in 1930, and is founded on well-established physical laws. As such, decades of astrophysical research have been based upon the theory. Yet, somehow the star that went supernova as SNLS-03D3bb reached about two solar masses before exploding.

"It should not be possible to break this limit," says Howell, "but nature has found a way. So now we have to figure out how nature did it."

In a separate News & Views article on the research in the same issue of Nature, University of Oklahoma professor David Branch has dubbed this the “Champagne Supernova,” since extreme explosions that offer new insight into the inner workings of supernovae are an obvious cause for celebration.

The team speculates that there are at least two possible explanations for how this white dwarf got so fat before it exploded. One is that the original star was rotating so fast that centrifugal force kept gravity from crushing it at the usual limit. Another is that the blast was in fact the result of two white dwarfs merging, such that the body was only briefly more massive than the Chandrasekhar limit before exploding. Observations of the supernova were obtained at the Canada-France-Hawaii telescope and the Keck telescope, both located on Mauna Kea in Hawaii.

Since Type Ia supernovae usually have about the same brightness, they can be used to map distances in the universe. In 1998 they were used in the surprising discovery that the universe is accelerating. While the authors are confident that the discovery of a supernova that doesn't follow the rules does not undermine this result, it will make them more cautious about using them in the future.

University of Toronto postdoctoral fellow Mark Sullivan, a coauthor on the research, says, “This supernovae muddies the waters. We now know these rogue supernovae are out there which might throw off our cosmology results if we aren't careful about identifying them.”

Source: University of Toronto

Explore further: Short, sharp shocks let slip the stories of supernovae

Related Stories

Distant supernova split four ways by gravitational lens

Mar 05, 2015

Over the past several decades, astronomers have come to realize that the sky is filled with magnifying glasses that allow the study of very distant and faint objects barely visible with even the largest telescopes.

Spacecraft Integral manoeuvres for the future

Jan 26, 2015

Since 2002, ESA's Integral spacecraft has been observing some of the most violent events in the Universe, including gamma-ray bursts and black holes. While it still has years of life ahead, its fuel will ...

Recommended for you

Hubble observes one-of-a-kind star nicknamed 'Nasty'

May 21, 2015

Astronomers using NASA's Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is ...

Galaxy's snacking habits revealed

May 20, 2015

A team of Australian and Spanish astronomers have caught a greedy galaxy gobbling on its neighbours and leaving crumbs of evidence about its dietary past.

Supernova ignition surprises scientists

May 20, 2015

Scientists have captured the early death throes of supernovae for the first time and found that the universe's benchmark explosions are much more varied than expected.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
1 / 5 (2) Jul 09, 2009
THE KEY: NUCLEAR REST MASS DATA

The key to the cosmos is recorded in 3,000 data points representing the rest masses of all of the atoms in the visible universe [ http://tinyurl.com/2otxps ]

See also the paper published in the Journal of Fusion Energy 20 (2001) 197-201 [ http://tinyurl.com/38un57 ].

With kind regards,
Oliver K. Manuel
http://www.omatumr.com

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.