SN 2003fg

Coordinates: 14^h 16^m 18^s, +52° 14′ 00″

SN 2003fg
Observation data (Epoch J2000.0)
Supernova type	aberrant Ia
Right ascension	14h 16m 18.78s
Declination	+52° 14' 55.4
Galactic coordinates	096.3812 +60.2821
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 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.^[1] It was nicknamed after the 1996 song "Champagne Supernova" by English rock band Oasis.^[2]

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 type Ia 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 × 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.^[3]

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.^[4]

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.^[1] The supernova occurred in a galaxy some 4 billion light-years from Earth.

References

1. ^ ^{a b} Howell, D. Andrew (21 September 2006). "The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star". Nature (London, United Kingdom: Nature Publishing Group) 443: 308–311. arXiv:astro-ph/0609616. Bibcode 2006Natur.443..308H. doi:10.1038/nature05103. ISSN 0028-0836. http://www.nature.com/nature/journal/v443/n7109/full/nature05103.html. Retrieved 9 August 2011. 
2. ^ Branch, David (21 September 2006). "Astronomy: Champagne supernova". Nature (London, United Kingdom: Nature Publishing Group) 443 (7109): 283–284. Bibcode 2006Natur.443..283B. doi:10.1038/443283a. ISSN 0028-0836. OCLC 01586310. http://www.nature.com/nature/journal/v443/n7109/full/443283a.html. Retrieved 1 October 2010. 
3. ^ Nugent, Peter (September 20, 2006). "The Weirdest Type Ia Supernova Yet". Research News (Berkeley, California: Lawrence Berkeley National Laboratory). http://www.lbl.gov/Science-Articles/Archive/Phys-weird-supernova.html. Retrieved 2006-11-02. 
4. ^ McKee, Maggie (20 September 2006). "Bizarre supernova breaks all the rules". New Scientist (United Kingdom: Reed Business Information). ISSN 0262-4079. http://www.newscientist.com/article/dn10114. Retrieved 2007-01-08. 

External links

• SN 2003fg - SIMBAD
• 'Champagne supernova' challenges understanding of how supernovae work - University of Toronto
• Cosmos Magazine - "Rebellious supernova confronts dark energy"
• 'Champagne Supernova' breaks astronomical rules - CBC
• Astronomy: Champagne supernova - Nature (subscription site)
• Supernovae - NASA GSFC