SN 2003fg
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| SN 2003fg | |
| Observation data (Epoch ) | |
|---|---|
| Supernova type | aberrant Ia |
| Discovery Date | 2003 |
| Physical characteristics | |
| Progenitor | ? |
| Progenitor type | ? |
| Colour (B-V) | ? |
| Notable features | Super Chandrasekhar |
The SN 2003fg (designated SNLS-03D3bb by the Canada-France-Hawaii Supernova Legacy Survey, which discovered it, and sometimes called the "Champagne Supernova" ), was an aberrant type Ia supernova discovered in 2003 and described in the journal Nature on September 21 of 2006. It was nicknamed after the 1995 song "Champagne Supernova" by Britpop group Oasis.
It may potentially revolutionize thinking about the physics of supernovae because of its highly unusual nature, in particular the mass of its progenitor. According to the current understanding, white dwarf stars go supernova when they approach 1.4 solar masses (1.4 times the mass of the Sun), termed the Chandrasekhar limit; the explosion occurs when the central density grows to a critical 2 x 109 g/cm3. The mass added to the star is believed to be donated by a companion star, either from the companion's stellar wind or the overflow of its Roche lobe as it evolves.
However, the progenitor of SN 2003fg reached two solar masses before exploding, more massive than thought possible. The primary mechanism invoked to explain how a white dwarf can exceed the Chandrasekhar mass is unusually rapid rotation; the added support effectively increases the critical mass. An alternative explanation is that the explosion resulted from the merger of two white dwarfs. The evidence indicating a higher than normal mass comes from the light curve and spectra of the supernova --- while it was particularly overluminous the kinetic energies measured from ejecta signatures in the spectra appeared smaller than usual. The explanation is that more of the total kinetic energy budget was expended climbing out of the deeper than usual potential well.
This is important because the brightness of type Ia supernovae was thought to be essentially uniform, making them useful "standard candles" in measuring distances in the universe. Such an aberrant type Ia supernova could throw distances and other scientific work into doubt, however the light curve characteristics of SNLS-03D3bb were such that it would never have been mistaken for an ordinary high-redshift Type Ia supernova.
The discovery was made on the Canada-France-Hawaii Telescope and the Keck Telescope, both on Mauna Kea in Hawaii, and announced by researchers at the University of Toronto. The supernova occurred in a galaxy some 4 billion light-years from Earth.
[edit] References
- "The Weirdest Type Ia Supernova Yet", Lawrence Berkeley National Laboratory, September 20, 2006. Retrieved on 2006-11-02.
- "Bizarre Supernova Breaks All The Rules", NewScientist, September 20, 2006. Retrieved on 2007-01-08.
