SN 2003fg

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

SN 2003fg
Other designationsSN 2003fg, SNLS 03D3bb
Spectral classaberrant Ia
Date2003
Right ascension14h 16m 18.78s
Declination+52° 14' 55.4
EpochJ2000.0
Galactic coordinates096.3812 +60.2821
Notable featuresSuper Chandrasekhar

SN 2003fg, sometimes called the "Champagne Supernova", was an unusual Type Ia supernova. It was discovered in 2003 with 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. It was nicknamed after the 1996 song "Champagne Supernova" by English rock band Oasis.[2]

It was unusual because of the mass of its progenitor. According to the current understanding, white dwarf stars explode as Type Ia supernovas when their mass approaches 1.4 solar masses, termed the Chandrasekhar limit. 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. 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 the spectra appeared smaller than usual. One proposed 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 SN 2003fg were such that it would never have been mistaken for an ordinary high-redshift Type Ia supernova.

References

  1. ^ Howell, D. Andrew (21 September 2006). "The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star". Nature. 443 (7109): 308–311. arXiv:astro-ph/0609616. Bibcode:2006Natur.443..308H. doi:10.1038/nature05103. PMID 16988705. Retrieved 9 August 2011.
  2. ^ Branch, David (21 September 2006). "Astronomy: Champagne supernova". Nature. 443 (7109): 283–284. Bibcode:2006Natur.443..283B. doi:10.1038/443283a. PMID 16988699. Retrieved 1 October 2010.
  3. ^ Nugent, Peter (September 20, 2006). "The Weirdest Type Ia Supernova Yet". Research News. Retrieved 2006-11-02.
  4. ^ McKee, Maggie (20 September 2006). "Bizarre supernova breaks all the rules". New Scientist. Retrieved 2007-01-08.

External links

Champagne (color)

The color champagne is a name given for various very pale tints of yellowish-orange that are close to beige. The color's name is derived from the typical color of the beverage Champagne.

Champagne Supernova

"Champagne Supernova" is a song by English rock band Oasis, written by guitarist Noel Gallagher. The seven-minute anthem is the closing track on the album (What's the Story) Morning Glory?. Though only released as a single in Australia, US, Canada, France and New Zealand in 1996, a music video directed by Nigel Dick was released to music channels and, as a result, the song received significant television and radio airplay.

The song was released in the US as a radio single to great success, becoming the band's second No. 1 single on the Modern Rock Tracks chart. It also peaked at No. 20 on the Billboard Hot 100 Airplay, becoming the band's third top 40 single on that chart. The song is considered a fan-favourite and has received widespread critical acclaim. The song is also included on Oasis' compilation album Stop the Clocks and on the US release of Time Flies... 1994–2009. Guest guitar and backing vocals are provided by Paul Weller.

Supernova SN 2003fg was nicknamed "Champagne Supernova" after the song.

Cosmic distance ladder

The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.

The ladder analogy arises because no single technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.

History of supernova observation

The known history of supernova observation goes back to 185 AD, when supernova SN 185 appeared, the oldest appearance of a supernova recorded by humankind. Several additional supernovae within the Milky Way galaxy have been recorded since that time, with SN 1604 being the most recent supernova to be observed in this galaxy.Since the development of the telescope, the field of supernova discovery has expanded to other galaxies. These occurrences provide important information on the distances of galaxies. Successful models of supernova behavior have also been developed, and the role of supernovae in the star formation process is now increasingly understood.

Index of physics articles (S)

The index of physics articles is split into multiple pages due to its size.

To navigate by individual letter use the table of contents below.

List of supernovae

This is a list of supernovae that are of historical significance. These include supernovae that were observed prior to the availability of photography, and individual events that have been the subject of a scientific paper that contributed to supernova theory.

Outline of astronomy

The following outline is provided as an overview of and topical guide to astronomy:

Astronomy – studies the universe beyond Earth, including its formation and development, and the evolution, physics, chemistry, meteorology, and motion of celestial objects (such as galaxies, planets, etc.) and phenomena that originate outside the atmosphere of Earth (such as the cosmic background radiation).

SN 2005gj

SN 2005gj was a supernova located approximately 864 million light years (265 million parsecs) away from Earth. It was discovered on September 29, 2005, by the Sloan Digital Sky Survey and the Nearby Supernova Factory. 2005gj was noted because it had qualities of both type Ia and type IIn supernovae, and because hydrogen emission lines were found in its spectrum (see hydrogen spectral series). These hydrogen lines, which were found on the spectrum at redshift z=0.0613, are thought to be indicative of interactions with a circumstellar medium (CSM; a donut-shaped, nebula-like ring of matter around a star) by the supernova's ejected matter or white dwarf progenitor. Such emission lines are extremely rare in Type Ia supernovae – only one other Type Ia, SN 2002ic, has been observed to exhibit the same properties. However, 2005jg's CSM interaction was much stronger and more clearly observed than 2002ic's. The mass-loss history 2005gj's hydrogen lines suggest has been cited as evidence that Luminous Blue Variable (LBV) hypergiants can be progenitors of thermonuclear supernovae.2005gj was also noted for its overluminosity. With a light curve that maximised 14–47 days after the initial observation, it was three times more luminous than SN 1991T (which was, at the time of its 1991 discovery, the brightest Ia supernova on record), 1.5 times more luminous than SN 2002ic, and close to 100 times more luminous than previously thought possible. Scientists Denis Leahy and Rachid Ouyed from the University of Calgary contend that the incidence of a quark nova, a very luminous process involving the degeneration of neutrons into their constituent quarks, could explain the unusual magnitude of the luminosity.

Supernova

A supernova ( plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of the life of a massive star, whose dramatic and catastrophic destruction is marked by one final, titanic explosion. This causes the sudden appearance of a "new" bright star, before slowly fading from sight over several weeks or months or years.

Supernovae are more energetic than novae. In Latin, nova means "new", referring astronomically to what appears to be a temporary new bright star. Adding the prefix "super-" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky in 1931.Only three Milky Way, naked-eye supernova events have been observed during the last thousand years, though many have been observed in other galaxies. The most recent directly observed supernova in the Milky Way was Kepler's Supernova in 1604, but the remnants of recent supernovae have also been found. Observations of supernovae in other galaxies suggest they occur on average about three times every century in the Milky Way, and that any galactic supernova would almost certainly be observable with modern astronomical telescopes.

Supernovae may expel much, if not all, of the material away from a star at velocities up to 30,000 km/s or 10% of the speed of light. This drives an expanding and fast-moving shock wave into the surrounding interstellar medium, and in turn, sweeping up an expanding shell of gas and dust, which is observed as a supernova remnant. Supernova nucleosynthesis is the major source of elements observed in nature., and play a significant role in enriching the interstellar medium with the heavier atomic mass chemical elements. Furthermore, the expanding shock waves from supernovae can trigger the formation of new stars. Supernova remnants are expected to accelerate a large fraction of galactic primary cosmic rays, but direct evidence for cosmic ray production was found only in a few of them so far. They are also potentially strong galactic sources of gravitational waves.Theoretical studies indicate that most supernovae are triggered by one of two basic mechanisms: the sudden re-ignition of nuclear fusion in a degenerate star or the sudden gravitational collapse of a massive star's core. In the first instance, a degenerate white dwarf may accumulate sufficient material from a binary companion, either through accretion or via a merger, to raise its core temperature enough to trigger runaway nuclear fusion, completely disrupting the star. In the second case, the core of a massive star may undergo sudden gravitational collapse, releasing gravitational potential energy as a supernova. While some observed supernovae are more complex than these two simplified theories, the astrophysical collapse mechanics have been established and accepted by most astronomers for some time.

Owing to the wide range of astrophysical consequences of these events, astronomers now deem supernova research, across the fields of stellar and galactic evolution, as an especially important area for investigation.

Type Ia supernova

A type Ia supernova (read "type one-a") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf.Physically, carbon–oxygen white dwarfs with a low rate of rotation are limited to below 1.44 solar masses (M☉). Beyond this, they reignite and in some cases trigger a supernova explosion. Somewhat confusingly, this limit is often referred to as the Chandrasekhar mass, despite being marginally different from the absolute Chandrasekhar limit where electron degeneracy pressure is unable to prevent catastrophic collapse. If a white dwarf gradually accretes mass from a binary companion, the general hypothesis is that its core will reach the ignition temperature for carbon fusion as it approaches the limit.

However, if the white dwarf merges with another white dwarf (a very rare event), it will momentarily exceed the limit and begin to collapse, again raising its temperature past the nuclear fusion ignition point. Within a few seconds of initiation of nuclear fusion, a substantial fraction of the matter in the white dwarf undergoes a runaway reaction, releasing enough energy (1–2×1044 J) to unbind the star in a supernova explosion.This type Ia category of supernovae produces consistent peak luminosity because of the uniform mass of white dwarfs that explode via the accretion mechanism. The stability of this value allows these explosions to be used as standard candles to measure the distance to their host galaxies because the visual magnitude of the supernovae depends primarily on the distance.

In May 2015, NASA reported that the Kepler space observatory observed KSN 2011b, a type Ia supernova in the process of exploding. Details of the pre-nova moments may help scientists better judge the quality of Type Ia supernovae as standard candles, which is an important link in the argument for dark energy.

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