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Encyclopedia > Supernova
Multiwavelength X-ray, infrared, and optical compilation image of Kepler's Supernova Remnant, SN 1604. (Chandra X-ray Observatory)
Multiwavelength X-ray, infrared, and optical compilation image of Kepler's Supernova Remnant, SN 1604. (Chandra X-ray Observatory)

A supernova (plural: supernovae or supernovas) is a stellar explosion. They are extremely luminous and cause a burst of radiation that may briefly outshine an entire galaxy before fading from view over several weeks or months. During this short interval, a supernova can radiate as much energy as the Sun could emit over its life span.[1] The explosion expels much or all of a star's material[2] at a velocity of up to a tenth the speed of light, driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. Look up supernova in Wiktionary, the free dictionary. ... Download high resolution version (750x750, 53 KB)Remnants of Keplers Supernova (SN 1604). ... Download high resolution version (750x750, 53 KB)Remnants of Keplers Supernova (SN 1604). ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... For other uses, see Infrared (disambiguation). ... See also list of optical topics. ... Kepler redirects here. ... Remnant of Keplers Supernova, SN 1604 Remnant of Tychos Nova, SN 1572 A supernova remnant (SNR) is the structure resulting from the gigantic explosion of a star in a supernova. ... Supernova 1604, also known as Keplers Supernova or Keplers Star, was a supernova in the Milky Way, in the constellation Ophiuchus. ... The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. ... For other uses, see Astronomy (disambiguation). ... For other uses, see Galaxy (disambiguation). ... For other uses, see Radiation (disambiguation). ... Sol redirects here. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ... Remnant of Keplers Supernova, SN 1604 Remnant of Tychos Nova, SN 1572 A supernova remnant (SNR) is the structure resulting from the gigantic explosion of a star in a supernova. ...


Several types of supernovae exist that may be triggered in one of two ways, involving either turning off or suddenly turning on the production of energy through nuclear fusion. After the core of an aging massive star ceases to generate energy from nuclear fusion, it may undergo sudden gravitational collapse into a neutron star or black hole, releasing gravitational potential energy that heats and expels the star's outer layers. Alternatively, a white dwarf star may accumulate sufficient material from a stellar companion (usually through accretion, rarely via a merger) to raise its core temperature enough to ignite carbon fusion, at which point it undergoes runaway nuclear fusion, completely disrupting it. Stellar cores whose furnaces have permanently gone out collapse when their masses exceed the Chandrasekhar limit, while accreting white dwarfs ignite as they approach this limit (roughly 1.38[3] times the mass of the Sun). White dwarfs are also subject to a different, much smaller type of thermonuclear explosion fueled by hydrogen on their surfaces called a nova. Solitary stars with a mass below approximately nine[4] solar masses, such as the Sun itself, evolve into white dwarfs without ever becoming supernovae. The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing sustainable fusion power. ... Projected timeline of the Suns life In astronomy, stellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. ... This article is about the astronomical object. ... This article or section does not cite its references or sources. ... For the story by Larry Niven, see Neutron Star (story). ... For other uses, see Black hole (disambiguation). ... Potential energy can be thought of as energy stored within a physical system. ... This article or section does not adequately cite its references or sources. ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... In astrophysics, the term accretion is used for at least two distinct processes. ... Carbon detonation is a violent re-ignition of thermonuclear fusion in a dead star, which produces Type Ia supernovae. ... The carbon burning process is a nuclear fusion reaction that occurs in massive stars (at least 4 MSun at birth) that have used up the lighter elements in their cores. ... This article is about Thermal runaway. ... The Chandrasekhar limit (named after the Indian astrophysicist Subrahmanyan Chandrasekhar) is the maximum nonrotating mass which can be supported against gravitational collapse by electron degeneracy pressure. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... This article does not cite its references or sources. ... Artists conception of a white dwarf star accreting hydrogen from a larger companion A nova (pl. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ...


On average, supernovae occur about once every 50 years in a galaxy the size of the Milky Way[5] and play a significant role in enriching the interstellar medium with heavy elements. Furthermore, the expanding shock waves from supernova explosions can trigger the formation of new stars.[6] For other uses, see Milky Way (disambiguation). ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its nucleus. ...


Nova (plural novae) means "new" in Latin, referring to what appears to be a very bright new star shining in the celestial sphere; the prefix "super-" distinguishes supernovae from ordinary novae, which also involve a star increasing in brightness, though to a lesser extent and through a different mechanism. According to Merriam-Webster's Collegiate Dictionary, the word supernova was first used in print in 1926. Latin was the language originally spoken in the region around Rome called Latium. ... The celestial sphere is divided by the celestial equator. ... In linguistics, a prefix is a type of affix that precedes the morphemes to which it can attach. ... Artists conception of a white dwarf star accreting hydrogen from a larger companion A nova (pl. ... 1888 advertisement for Websters Dictionary Websters Dictionary is the common title given to English language dictionaries in the United States, derived from American lexicographer Noah Webster. ...

Contents

Observation history

The Crab Nebula is a pulsar wind nebula associated with the 1054 supernova.
The Crab Nebula is a pulsar wind nebula associated with the 1054 supernova.

The earliest recorded supernova, SN 185, was viewed by Chinese astronomers in 185 CE. The widely observed supernova SN 1054 produced the Crab Nebula. Supernovae SN 1572 and SN 1604, the last to be observed in the Milky Way galaxy, had notable effects on the development of astronomy in Europe because they were used to argue against the Aristotelian idea that the world beyond the Moon and planets was immutable.[7] The Crab Nebula is a pulsar wind nebula associated with the 1054 supernova. ... Image File history File linksMetadata Download high resolution version (2224x2212, 3149 KB) Summary Image: A Giant Hubble Mosaic of the Crab Nebula Source: http://hubblesite. ... Image File history File linksMetadata Download high resolution version (2224x2212, 3149 KB) Summary Image: A Giant Hubble Mosaic of the Crab Nebula Source: http://hubblesite. ... The Crab Nebula (catalogue designations M 1, NGC 1952, Taurus A) is a supernova remnant in the constellation of Taurus. ... A pulsar wind nebula (also known as a plerion, Greek for full) is a synchrotron nebula powered by the relativistic wind of an energetic pulsar. ... SN 1054 was a supernova that was widely seen on Earth in the year 1054. ... SN 185 is a supernova event that occured in the year 185 CE in the constellation Centaurus. ... Galileo is often referred to as the Father of Modern Astronomy. ... For other uses, see number 185. ... SN 1054 was a supernova that was widely seen on Earth in the year 1054. ... The Crab Nebula (catalogue designations M 1, NGC 1952, Taurus A) is a supernova remnant in the constellation of Taurus. ... X-ray image of the expanding cloud of debris and high energy electrons from Tychos supernova. ... Supernova 1604, also known as Keplers Supernova or Keplers Star, was a supernova in the Milky Way, in the constellation Ophiuchus. ... For other uses, see Milky Way (disambiguation). ... For other uses, see Aristotle (disambiguation). ...


Since the development of the telescope, the field of supernova discovery has enlarged to other galaxies, starting with the 1885 observation of supernova S Andromedae in the Andromeda galaxy. Supernovae provide important information on cosmological distances.[8] During the twentieth century, successful models for each type of supernova were developed, and scientists' comprehension of the role of supernovae in the star formation process is growing. This article does not cite any references or sources. ... S Andromedae (also SN 1885A) was a supernova in the Andromeda Galaxy, the only one seen in that galaxy so far by astronomers, and the first ever noted outside the Milky Way. ... The Andromeda Galaxy (IPA: , also known as Messier 31, M31, or NGC 224; older texts often called it the Great Andromeda Nebula) is a spiral galaxy approximately 2. ...


Some of the most distant supernovae recently observed appeared dimmer than expected. This has provided evidence that the expansion of the universe may be accelerating.[9][10] The accelerating universe is the observation that the universe appears to be expanding at an accelerated rate. ...


Discovery

Because supernovae are relatively rare events, occurring about once every 50 years in a galaxy like the Milky Way,[5] many galaxies must be monitored regularly in order to obtain a good sample of supernovae to study.


Supernovae in other galaxies cannot be predicted with any meaningful accuracy. When they are discovered, they are already in progress.[11] Most scientific interest in supernovae—as standard candles for measuring distance, for example—require an observation of their peak luminosity. It is therefore important to discover them well before they reach their maximum. Amateur astronomers, who greatly outnumber professional astronomers, have played an important role in finding supernovae, typically by looking at some of the closer galaxies through an optical telescope and comparing them to earlier photographs. A standard candle is an astronomical object that has a known luminosity. ... It has been suggested that this article or section be merged with Skygazing. ... Eight Inch refracting telescope. ...


Towards the end of the 20th century, astronomers increasingly turned to computer-controlled telescopes and CCDs for hunting supernovae. While such systems are popular with amateurs, there are also larger installations like the Katzman Automatic Imaging Telescope.[12] Recently, the Supernova Early Warning System (SNEWS) project has also begun using a network of neutrino detectors to give early warning of a supernova in the Milky Way galaxy.[13][14] A neutrino is a particle that is produced in great quantities by a supernova explosion,[15] and it is not obscured by the interstellar gas and dust of the galactic disk. A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... The Katzman Automatic Imaging Telescope (KAIT) is an automated telescope used in the search for supernovae. ... The Supernova Early Warning System (SNEWS) is a network of neutrino detectors designed to give early warning to astronomers in the event of a supernova in our Milky Way galaxy. ... For other uses, see Neutrino (disambiguation). ... Helium atom (schematic) Showing two protons (red), two neutrons (green) and two electrons (yellow). ...


Supernova searches fall into two classes: those focused on relatively nearby events and those looking for explosions farther away. Because of the expansion of the universe, the distance to a remote object with a known emission spectrum can be estimated by measuring its Doppler shift (or redshift); on average, more distant objects recede with greater velocity than those nearby, and so have a higher redshift. Thus the search is split between high redshift and low redshift, with the boundary falling around a redshift range of z = 0.1–0.3[16]—where z is a dimensionless measure of the spectrum's frequency shift. This box:      The metric expansion of space is a key part of sciences current understanding of the universe, whereby spacetime itself is described by a metric which changes over time in such a way that the spatial dimensions grow or stretch as the universe gets older. ... The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ... This article is about the physical phenomenon. ...


High redshift searches for supernovae usually involve the observation of supernova light curves. These are useful for standard or calibrated candles to generate Hubble diagrams and make cosmological predictions. At low redshift, supernova spectroscopy is more practical than at high redshift, and this is used to study the physics and environments of supernovae.[17][18] Low redshift observations also anchor the low distance end of the Hubble curve, which is a plot of distance versus redshift for visible galaxies.[19][20]

See also: Hubble's law

This box:      Hubbles law is a statement in physical cosmology which states that the redshift in light coming from distant galaxies is proportional to their distance. ...

Naming convention

SN 1994D in the NGC 4526 galaxy (bright spot on the lower left). Image by NASA, ESA, The Hubble Key Project Team, and The High-Z Supernova Search Team
SN 1994D in the NGC 4526 galaxy (bright spot on the lower left). Image by NASA, ESA, The Hubble Key Project Team, and The High-Z Supernova Search Team

Supernova discoveries are reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams, which sends out a circular with the name it assigns to it. The name is formed by the year of discovery, immediately followed by a one or two-letter designation. The first 26 supernovae of the year get designated with an upper case letter from A to Z. Afterward, pairs of lower-case letters are used, starting with aa, ab, and so on.[21] Professional and amateur astronomers find several hundred supernovae each year (367 in 2005, 551 in 2006 and 572 in 2007). For example, the last supernova of 2005 was SN 2005nc, indicating that it was the 367th supernova found in 2005.[22][23] Image File history File links Download high resolution version (2608x2608, 708 KB) Beschreibung Hubble Space Telescope-Bild der Supernova 1994D (SN1994D) am Rand der Galaxie NGC 4526 (SN 1994D ist der helle Fleck unten links) Hubble Space Telescope-Bild of Supernova 1994D (SN1994D) in galaxy NGC 4526 (SN 1994D is... Image File history File links Download high resolution version (2608x2608, 708 KB) Beschreibung Hubble Space Telescope-Bild der Supernova 1994D (SN1994D) am Rand der Galaxie NGC 4526 (SN 1994D ist der helle Fleck unten links) Hubble Space Telescope-Bild of Supernova 1994D (SN1994D) in galaxy NGC 4526 (SN 1994D is... Supernova 1994D was a Type Ia supernova in the outskirts of galaxy NGC 4526. ... Supernova SN 1994D is visible in the NGC 4526 galaxy NGC 4526 is a spiral galaxy thats part of the Virgo cluster. ... For other uses, see NASA (disambiguation). ... This article is about the European Space Agency. ... IAU redirects here. ... The Central Bureau for Astronomical Telegrams (CBAT) is the official international clearing house for information relating to transient astronomical events. ...


Historical supernovae are known simply by the year they occurred: SN 185, SN 1006, SN 1054, SN 1572 (Tycho's Nova) and SN 1604 (Kepler's Star). Since 1885, the letter notation was used, even if there was only one supernova discovered that year (e.g. SN 1885A, 1907A, etc.)—this last happened with SN 1947A. The standard abbreviation "SN" is an optional prefix. SN 185 is a supernova event that occured in the year 185 CE in the constellation Centaurus. ... ... SN 1054 was a supernova that was widely seen on Earth in the year 1054. ... X-ray image of the expanding cloud of debris and high energy electrons from Tychos supernova. ... Supernova 1604, also known as Keplers Supernova or Keplers Star, was a supernova in the Milky Way, in the constellation Ophiuchus. ...


Classification

As part of the attempt to understand supernovae, astronomers have classified them according to the absorption lines of different chemical elements that appear in their spectra. The first element for a division is the presence or absence of a line caused by hydrogen. If a supernova's spectrum contains a line of hydrogen (known as the Balmer series in the visual portion of the spectrum) it is classified Type II; otherwise it is Type I. Among those types, there are subdivisions according to the presence of lines from other elements and the shape of the light curve (a graph of the supernova's apparent magnitude versus time).[24] A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... High resolution spectrum of the Sun showing thousands of elemental absorption lines (fraunhofer lines). ... This article is about the chemistry of hydrogen. ... Two of the balmer lines (α and β) are clearly visible in this emission spectrum of a deuterium lamp. ... In astronomy, a light curve is a graph of light intensity as a function of time. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ...

Supernova taxonomy[25]
Type Characteristics
Type I
Type Ia Lacks hydrogen and presents a singly-ionized silicon (Si II) line at 615.0 nm (nanometers), near peak light.
Type Ib Non-ionized helium (He I) line at 587.6 nm and no strong silicon absorption feature near 615 nm.
Type Ic Weak or no helium lines and no strong silicon absorption feature near 615 nm.
Type II
Type IIP Reaches a "plateau" in its light curve
Type IIL Displays a "linear" decrease in its light curve (linear in magnitude versus time).[26]

The supernovae of Type II can also be sub-divided based on their spectra. While most Type II supernova show very broad emission lines which indicate expansion velocities of many thousands of kilometres per second, some have relatively narrow features. These are called Type IIn, where the "n" stands for "narrow".[25] Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ... Ionization is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. ... Not to be confused with Silicone. ... A nanometre (American spelling: nanometer, symbol nm) (Greek: νάνος, nanos, dwarf; μετρώ, metrÏŒ, count) is a unit of length in the metric system, equal to one billionth of a metre (or one millionth of a millimetre), which is the current SI base unit of length. ... Type Ib and Ic supernovae are categories of stellar explosions. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... Type Ib and Ic supernovae are categories of stellar explosions. ... The expanding remnant of SN 1987A, a Type II-P supernova in the Large Magellanic Cloud. ... The expanding remnant of SN 1987A, a Type II-P supernova in the Large Magellanic Cloud. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... kilometre per second is an SI derived unit of both speed (scalar) and velocity (vector), signified by the symbol km/s or km s-1. ...


A few supernovae, such as SN 1987K and SN 1993J, appear to change types: they show lines of hydrogen at early times, but, over a period of weeks to months, become dominated by lines of helium. The term "Type IIb" is used to describe the combination of features normally associated with Types II and Ib.[25]


Current models

Type Ia

Main article: Type Ia supernova

There are several means by which a supernova of this type can form, but they share a common underlying mechanism. If a carbon-oxygen[a] white dwarf accreted enough matter to reach the Chandrasekhar limit of about 1.38 solar masses[3] (for a non-rotating star), it would no longer be able to support the bulk of its plasma through electron degeneracy pressure[27][28] and would begin to collapse. However, the current view is that this limit is not normally attained; increasing temperature and density inside the core ignite carbon fusion as the star approaches the limit (to within about 1%[29]), before collapse is initiated.[3] Within a few seconds, a substantial fraction of the matter in the white dwarf undergoes nuclear fusion, releasing enough energy (1–2 × 1044 joules)[30] to unbind the star in a supernova explosion.[31] An outwardly expanding shock wave is generated, with matter reaching velocities on the order of 5,000–20,000 km/s, or roughly 3% of the speed of light. There is also a significant increase in luminosity, reaching an absolute magnitude of -19.3 (or 5 billion times brighter than the Sun), with little variation.[32] Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ... For other uses, see Carbon (disambiguation). ... This article is about the chemical element and its most stable form, or dioxygen. ... This article or section does not adequately cite its references or sources. ... The Chandrasekhar limit (named after the Indian astrophysicist Subrahmanyan Chandrasekhar) is the maximum nonrotating mass which can be supported against gravitational collapse by electron degeneracy pressure. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Carbon detonation is a violent re-ignition of thermonuclear fusion in a dead star, which produces Type Ia supernovae. ... The carbon burning process is a nuclear fusion reaction that occurs in massive stars (at least 4 MSun at birth) that have used up the lighter elements in their cores. ... The joule (IPA: or ) (symbol: J) is the SI unit of energy. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ...


One model for the formation of this category of supernova is a close binary star system. The larger of the two stars is the first to evolve off the main sequence, and it expands to form a red giant.[33] The two stars now share a common envelope, causing their mutual orbit to shrink. The giant star then sheds most of its envelope, losing mass until it can no longer continue nuclear fusion. At this point it becomes a white dwarf star, composed primarily of carbon and oxygen.[34][35] Eventually the secondary star also evolves off the main sequence to form a red giant. Matter from the giant is accreted by the white dwarf, causing the latter to increase in mass. For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing sustainable fusion power. ...


Another model for the formation of a Type Ia explosion involves the merger of two white dwarf stars, with the combined mass momentarily exceeding the Chandrasekhar limit.[36] A white dwarf could also accrete matter from other types of companions, including a main sequence star (if the orbit is sufficiently close).


Type Ia supernovae follow a characteristic light curve—the graph of luminosity as a function of time—after the explosion. This luminosity is generated by the radioactive decay of nickel-56 through cobalt-56 to iron-56.[32] The peak luminosity of the light curve was believed to be consistent across Type Ia supernovae (the vast majority of which are initiated with a uniform mass via the accretion mechanism), allowing them to be used as a secondary[37] standard candle to measure the distance to their host galaxies.[38] However, recent discoveries reveal that there is some evolution in the average lightcurve width, and thus in the intrinsic luminosity of Supernovae, although significant evolution is found only over a large redshift baseline.[39] In astronomy, a light curve is a graph of light intensity as a function of time. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... For other uses, see Nickel (disambiguation). ... For other uses, see Cobalt (disambiguation). ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... A standard candle is an astronomical object that has a known luminosity. ... For other uses, see Galaxy (disambiguation). ...


Type Ib and Ic

These events, like supernovae of Type II, are probably massive stars running out of fuel at their centers; however, the progenitors of Types Ib and Ic have lost most of their outer (hydrogen) envelopes due to strong stellar winds or else from interaction with a companion.[40] Type Ib supernovae are thought to be the result of the collapse of a massive Wolf-Rayet star. There is some evidence that a few percent of the Type Ic supernovae may be the progenitors of gamma ray bursts (GRB), though it is also believed that any hydrogen-stripped, Type Ib or Ic supernova could be a GRB, dependent upon the geometry of the explosion.[41] Type Ib and Ic supernovae are categories of stellar explosions. ... A solar wind is a stream of particles (mostly high-energy protons ~ 500 keV) which are ejected from the upper atmosphere of a star (in the case of a star other than the Earths Sun, it may be called a stellar wind instead). ... Hubble Space Telescope image of nebula M1-67 around Wolf Rayet star WR 124 Wolf-Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses), and are losing their mass rapidly by means of a very strong stellar wind, with speeds up to 2000... In astronomy, gamma-ray bursts (GRBs) are flashes of gamma rays that last from seconds to hours, the longer ones being followed by several days of X-ray afterglow. ...


Type II

Main article: Type II supernova
The onion-like layers of a massive, evolved star just prior to core collapse. (Not to scale.)
The onion-like layers of a massive, evolved star just prior to core collapse. (Not to scale.)

Stars with at least nine solar masses of material evolve in a complex fashion.[4] In the core of the star, hydrogen is fused into helium and the thermal energy released creates an outward pressure, which maintains the core in hydrostatic equilibrium and prevents collapse. The expanding remnant of SN 1987A, a Type II-P supernova in the Large Magellanic Cloud. ... Image File history File links Evolved_star_fusion_shells. ... Image File history File links Evolved_star_fusion_shells. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... In thermal physics, thermal energy is the energy portion of a system that increases with its temperature. ... Hydrostatic equilibrium occurs when compression due to gravity is balanced by a pressure gradient which creates a pressure gradient force in the opposite direction. ...


When the core's supply of hydrogen is exhausted, this outward pressure is no longer created. The core begins to collapse, causing a rise in temperature and pressure which becomes great enough to ignite the helium and start a helium-to-carbon fusion cycle, creating sufficient outward pressure to halt the collapse. The core expands and cools slightly, with a hydrogen-fusion outer layer, and a hotter, higher pressure, helium-fusion center. (Other elements such as magnesium, sulfur and calcium are also created and in some cases burned in these further reactions.) This article or section does not cite its references or sources. ... For other uses, see Carbon (disambiguation). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... This article is about the chemical element. ... For other uses, see Calcium (disambiguation). ...


This process repeats several times, and each time the core collapses and the collapse is halted by the ignition of a further process involving more massive nuclei and higher temperatures and pressures. Each layer is prevented from collapse by the heat and outward pressure of the fusion process in the next layer inward; each layer also burns hotter and quicker than the previous one – the final burn of silicon to nickel consumes its fuel in around one day, or a few days.[42] The star becomes layered like an onion, with the burning of more easily fused elements occurring in larger shells.[43][44]


In the later stages, increasingly heavier elements undergo nuclear fusion, and the binding energy of the relevant nuclei increases. Fusion produces progressively lower levels of energy, and also at higher core energies photodisintegration and electron capture occur which cause energy loss in the core and a general acceleration of the fusion processes to maintain equilibrium.[42] This escalation culminates with the production of nickel-56, which is unable to produce energy through fusion (but does produce iron-56 through radioactive decay).[45] As a result, a nickel-iron core[46] builds up that cannot produce any further outward pressure on a scale needed to support the rest of the structure. It can only support the overlaying mass of the star through the degeneracy pressure of electrons in the core. If the star is sufficiently large, then the iron-nickel core will eventually exceed the Chandrasekhar limit (1.38 solar masses), at which point this mechanism catastrophically fails. The forces holding atomic nuclei apart in the innermost layer of the core suddenly give way, the core implodes due to its own mass, and no further fusion process can ignite or prevent collapse this time.[27] Binding energy is the energy required to disassemble a whole into separate parts. ... Photodisintegration is a physics process in which extremely high energy Gamma rays impact an atomic nucleus and cause it to break apart in a nuclear fission reaction. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... Look up equilibrium in Wiktionary, the free dictionary. ... In astrophysics, silicon burning is a nuclear fusion reaction which occurs in massive stars. ... Degenerate matter is matter which has sufficiently high density that the dominant contribution to its pressure arises from the Pauli exclusion principle. ... For other uses, see Electron (disambiguation). ... The Chandrasekhar limit (named after the Indian astrophysicist Subrahmanyan Chandrasekhar) is the maximum nonrotating mass which can be supported against gravitational collapse by electron degeneracy pressure. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... In an explosion (top), force radiates away from a source. ...


Core collapse

See also: Gravitational collapse

The core collapses in on itself with velocities reaching 70,000 km/s (0.23c),[47] resulting in a rapid increase in temperature and density. The energy loss processes operating in the core cease to be in equilibrium. Through photodisintegration, gamma rays decompose iron into helium nuclei and free neutrons, absorbing energy, whilst electrons and protons merge via electron capture, producing neutrons and electron neutrinos which escape. This article or section does not cite its references or sources. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... Photodisintegration is a physics process in which extremely high energy Gamma rays impact an atomic nucleus and cause it to break apart in a nuclear fission reaction. ... This article is about electromagnetic radiation. ... This article or section does not adequately cite its references or sources. ... For other uses, see Electron (disambiguation). ... For other uses, see Proton (disambiguation). ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... For other uses, see Neutrino (disambiguation). ...


In a typical Type II supernova, the newly formed neutron core has an initial temperature of about 100 billion kelvins (100 GK); 6000 times the temperature of the sun's core. Much of this thermal energy must be shed for a stable neutron star to form (otherwise the neutrons would "boil away"), and this is accomplished by a further release of neutrinos.[48] These 'thermal' neutrinos form as neutrino-antineutrino pairs of all flavors, and total several times the number of electron-capture neutrinos.[49] About 1046 joules of gravitational energy—about 10% of the star's rest mass—is converted into a ten-second burst of neutrinos; the main output of the event.[42][50] These carry away energy from the core and accelerate the collapse, while some neutrinos are absorbed by the star's outer layers and begin the supernova explosion.[51] For other uses, see Kelvin (disambiguation). ... Neutrino oscillation is a quantum mechanical phenomenon predicted by Bruno Pontecorvo whereby a neutrino created with a specific lepton flavor (electron, muon or tau) can later be measured to have a different flavor. ...


The inner core eventually reaches typically 30 km diameter,[42] and a density comparable to that of an atomic nucleus, and further collapse is abruptly stopped by strong force interactions and by degeneracy pressure of neutrons. The infalling matter, suddenly halted, rebounds, producing a shock wave that propagates outward. Computer simulations indicate that this expanding shock does not directly cause the supernova explosion;[42] rather, it stalls within milliseconds[52] in the outer core as energy is lost through the dissociation of heavy elements, and a process that is not clearly understood is necessary to allow the outer layers of the core to reabsorb around 1044 joules[b] (1 foe) of energy, producing the visible explosion.[53] Current research focuses upon rotational and magnetic effects as the basis for this process.[42] The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... The strong nuclear force or strong interaction (also called color force or colour force) is a fundamental force of nature which affects only quarks and antiquarks, and is mediated by gluons in a similar fashion to how the electromagnetic force is mediated by photons. ... Degenerate matter is matter which has sufficiently high density that the dominant contribution to its pressure arises from the Pauli exclusion principle. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... One millisecond is one-thousandth of a second. ... A foe is a unit of energy equal to 1044 joules. ... This article is about rotation as a movement of a physical body. ... For the indie-pop band, see The Magnetic Fields. ...

Within a massive, evolved star (a) the onion-layered shells of elements undergo fusion, forming an iron core (b) that reaches Chandrasekhar-mass and starts to collapse. The inner part of the core is compressed into neutrons (c), causing infalling material to bounce (d) and form an outward-propagating shock front (red). The shock starts to stall (e), but it is re-invigorated by neutrino interaction. The surrounding material is blasted away (f), leaving only a degenerate remnant.
Within a massive, evolved star (a) the onion-layered shells of elements undergo fusion, forming an iron core (b) that reaches Chandrasekhar-mass and starts to collapse. The inner part of the core is compressed into neutrons (c), causing infalling material to bounce (d) and form an outward-propagating shock front (red). The shock starts to stall (e), but it is re-invigorated by neutrino interaction. The surrounding material is blasted away (f), leaving only a degenerate remnant.

When the progenitor star is below about 20 solar masses (depending on the strength of the explosion and the amount of material that falls back), the degenerate remnant of a core collapse is a neutron star.[47] Above this mass the remnant collapses to form a black hole.[44][54] (This type of collapse is one of many candidate explanations for gamma ray bursts—producing a large burst of gamma rays through a still theoretical hypernova explosion.)[55] The theoretical limiting mass for this type of core collapse scenario was estimated around 40–50 solar masses. Image File history File links Core_collapse_scenario. ... Image File history File links Core_collapse_scenario. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... For the story by Larry Niven, see Neutron Star (story). ... For other uses, see Black hole (disambiguation). ... The image above shows the optical afterglow of gamma ray burst GRB-990123 taken on January 23, 1999. ... This article is about electromagnetic radiation. ... This article needs additional references or sources for verification. ...


Above 50 solar masses, stars were believed to collapse directly into a black hole without forming a supernova explosion,[56] although uncertainties in models of supernova collapse make accurate calculation of these limits difficult. In fact recent evidence has shown stars in the range of about 140–250 solar masses, with a relatively low proportion of elements more massive than helium, may be capable of forming pair-instability supernovae without leaving behind a black hole remnant. This rare type of supernova is formed by an alternate mechanism (partially analogous to that of Type Ia explosions) that does not require an iron core. An example is the Type II supernova SN 2006gy, with an estimated 150 solar masses, that demonstrated the explosion of such a massive star differed fundamentally from previous theoretical predictions.[57][58] This illustration explains the pair-instability supernova process that astronomers think triggered the explosion in SN 2006gy. ... SN 2006gy and the core of its home galaxy, NGC 1260, viewed in x-ray light from the Chandra X-ray Observatory. ...


Light curves and unusual spectra

This graph of the luminosity (relative to the Sun) as a function of time shows the characteristic shapes of the light curves for a Type II-L and II-P supernova.
This graph of the luminosity (relative to the Sun) as a function of time shows the characteristic shapes of the light curves for a Type II-L and II-P supernova.

The light curves for Type II supernovae are distinguished by the presence of hydrogen Balmer absorption lines in the spectra. These light curves have an average decay rate of 0.008 magnitudes per day; much lower than the decay rate for Type I supernovae. Type II are sub-divided into two classes, depending on whether there is a plateau in their light curve (Type II-P) or a linear decay rate (Type II-L). The net decay rate is higher at 0.012 magnitudes per day for Type II-L compared to 0.0075 magnitudes per day for Type II-P. The difference in the shape of the light curves is believed to be caused, in the case of Type II-L supernovae, by the expulsion of most of the hydrogen envelope of the progenitor star.[26] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Two of the balmer lines (α and β) are clearly visible in this emission spectrum of a deuterium lamp. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ...


The plateau phase in Type II-P supernovae is due to a change in the opacity of the exterior layer. The shock wave ionizes the hydrogen in the outer envelope, which greatly increases the opacity. This prevents photons from the inner parts of the explosion from escaping. Once the hydrogen cools sufficiently to recombine, the outer layer becomes transparent.[59] A substance or object that is opaque is neither transparent nor translucent. ... ...


Of the Type II supernovae with unusual features in their spectra, Type IIn supernovae may be produced by the interaction of the ejecta with circumstellar material.[60] Type IIb supernovae are likely massive stars which have lost most, but not all, of their hydrogen envelopes through tidal stripping by a companion star. As the ejecta of a Type IIb expands, the hydrogen layer quickly becomes optically thin and reveals the deeper layers.[61] Comet Shoemaker-Levy 9 after breaking up under the influence of Jupiters tidal forces. ...


Asymmetry

A long-standing puzzle surrounding supernovae has been a need to explain why the compact object remaining after the explosion is given a large velocity away from the core.[62] (Neutron stars are observed, as pulsars, to have high velocities; black holes presumably do as well, but are far harder to observe in isolation.) This kick can be substantial, propelling an object of more than a solar mass at a velocity of 500 km/s or greater. This displacement is believed to be caused by an asymmetry in the explosion, but the mechanism by which this momentum is transferred to the compact object has remained a puzzle. Some explanations for this kick include convection in the collapsing star and jet production during neutron star formation. For the story by Larry Niven, see Neutron Star (story). ... It has been suggested that Radio pulsar be merged into this article or section. ... For other uses, see Black hole (disambiguation). ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ...

This composite image shows X-ray (blue) and optical (red) radiation from the Crab Nebula's core region. A pulsar near the center is propelling particles to almost the speed of light. This neutron star is travelling at an estimated 375 km/s. NASA/CXC/HST/ASU/J. Hester et al. image credit.
This composite image shows X-ray (blue) and optical (red) radiation from the Crab Nebula's core region. A pulsar near the center is propelling particles to almost the speed of light.[63] This neutron star is travelling at an estimated 375 km/s.[64] NASA/CXC/HST/ASU/J. Hester et al. image credit.

One explanation for the asymmetry in the explosion is large-scale convection above the core. The convection can create variations in the local abundances of elements, resulting in uneven nuclear burning during the collapse, bounce and resulting explosion.[65] Image File history File links Download high-resolution version (2400x2400, 314 KB) A composite image of the Crab Nebula showing the X-ray (blue), and optical (red) images superimposed. ... Image File history File links Download high-resolution version (2400x2400, 314 KB) A composite image of the Crab Nebula showing the X-ray (blue), and optical (red) images superimposed. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... The Crab Nebula (catalogue designations M 1, NGC 1952, Taurus A) is a supernova remnant in the constellation of Taurus. ... It has been suggested that Radio pulsar be merged into this article or section. ... For other uses, see NASA (disambiguation). ...


Another explanation is that accretion of gas onto the central neutron star can create a disk that drives highly directional jets, propelling matter at a high velocity out of the star, and driving transverse shocks that completely disrupt the star. These jets might play a crucial role in the resulting supernova explosion.[66][67] (A similar model is now favored for explaining long gamma ray bursts.) An accretion disc (or accretion disk) is a structure formed by material falling into a gravitational source. ... In astronomy, gamma-ray bursts (GRBs) are flashes of gamma rays that last from seconds to hours, the longer ones being followed by several days of X-ray afterglow. ...


Initial asymmetries have also been confirmed in Type Ia supernova explosions through observation. This result may mean that the initial luminosity of this type of supernova may depend on the viewing angle. However, the explosion becomes more symmetrical with the passage of time. Early asymmetries are detectable by measuring the polarization of the emitted light.[68]


Type Ia vis-à-vis core collapse

Because they have a similar functional model, Types Ib, Ic and various Types II supernovae are collectively called Core Collapse supernovae. A fundamental difference between Type Ia and Core Collapse supernovae is the source of energy for the radiation emitted near the peak of the light curve. The progenitors of Core Collapse supernovae are stars with extended envelopes that can attain a degree of transparency with a relatively small amount of expansion. Most of the energy powering the emission at peak light is derived from the shock wave that heats and ejects the envelope.[69]


The progenitors of Type Ia supernovae, on the other hand, are compact objects, much smaller (but more massive) than the Sun, that must expand (and therefore cool) enormously before becoming transparent. Heat from the explosion is dissipated in the expansion and is not available for light production. The radiation emitted by Type Ia supernovae is thus entirely attributable to the decay of radionuclides produced in the explosion; principally nickel-56 (with a half-life of 6.1 days) and its daughter cobalt-56 (with a half-life of 77 days). Gamma rays emitted during this nuclear decay are absorbed by the ejected material, heating it to incandescence. A radionuclide is an atom with an unstable Goat, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created radiation particle within the nucleus, or else to an atomic electron (see internal conversion) . The radionuclide, in this process, undergoes radioactive decay... For other uses, see Nickel (disambiguation). ... For other uses, see Cobalt (disambiguation). ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... Molten glassy material glows orange with incandescence in a vitrification experiment. ...


As the material ejected by a Core Collapse supernova expands and cools, radioactive decay eventually takes over as the main energy source for light emission in this case also. A bright Type Ia supernova may expel 0.5–1.0 solar masses of nickel-56,[70] while a Core Collapse supernova probably ejects closer to 0.1 solar mass of nickel-56.[71] In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ...


Interstellar impact

Source of heavy elements

Supernovae are a key source of elements heavier than oxygen. These elements are produced by nuclear fusion (for iron-56 and lighter elements), and by nucleosynthesis during the supernova explosion for elements heavier than iron. Supernova are the most likely, although not undisputed, candidate sites for the r-process, which is a rapid form of nucleosynthesis that occurs under conditions of high temperature and high density of neutrons. The reactions produce highly unstable nuclei that are rich in neutrons. These forms are unstable and rapidly beta decay into more stable forms. Supernova nucleosynthesis refers to the production of new chemical elements inside supernovae. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its nucleus. ... This article is about the chemical element and its most stable form, or dioxygen. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing sustainable fusion power. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ... The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... This article or section does not adequately cite its references or sources. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ...


The r-process reaction, which is likely to occur in type II supernovae, produces about half of all the element abundance beyond iron, including plutonium, uranium and californium.[72] The only other major competing process for producing elements heavier than iron is the s-process in large, old red giant stars, which produces these elements much more slowly, and which cannot produce elements heavier than lead.[73] This article is about the radioactive element. ... This article is about the chemical element. ... General Name, Symbol, Number californium, Cf, 98 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (251) g·mol−1 Electron configuration [Rn] 5f10 7s2 Electrons per shell 2, 8, 18, 32, 28, 8, 2 Physical properties Phase solid... This article or section does not cite its references or sources. ... General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ...


Role in stellar evolution

Main article: Supernova remnant

The remnant of a supernova explosion consists of a compact object and a rapidly expanding shock wave of material. This cloud of material sweeps up the surrounding interstellar medium during a free expansion phase, which can last for up to two centuries. The wave then gradually undergoes a period of adiabatic expansion, and will slowly cool and mix with the surrounding interstellar medium over a period of about 10,000 years.[74] Remnant of Keplers Supernova, SN 1604 Remnant of Tychos Nova, SN 1572 A supernova remnant (SNR) is the structure resulting from the gigantic explosion of a star in a supernova. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ... In thermodynamics, an adiabatic process or an isocaloric process is a thermodynamic process in which no heat is transferred to or from the working fluid. ...


In standard astronomy, the Big Bang produced hydrogen, helium, and traces of lithium, while all heavier elements are synthesized in stars and supernovae. Supernovae tend to enrich the surrounding interstellar medium with metals, which for astronomers means all of the elements other than hydrogen and helium and is a different definition than that used in chemistry. For other uses, see Big Bang (disambiguation). ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... This article is about the chemical element. ... The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ...

Supernova remnant N 63A lies within a clumpy region of gas and dust in the Large Magellanic Cloud. NASA image.
Supernova remnant N 63A lies within a clumpy region of gas and dust in the Large Magellanic Cloud. NASA image.

These injected elements ultimately enrich the molecular clouds that are the sites of star formation.[75] Thus, each stellar generation has a slightly different composition, going from an almost pure mixture of hydrogen and helium to a more metal-rich composition. Supernovae are the dominant mechanism for distributing these heavier elements, which are formed in a star during its period of nuclear fusion, throughout space. The different abundances of elements in the material that forms a star have important influences on the star's life, and may decisively influence the possibility of having planets orbiting it. Image File history File links Size of this preview: 790 × 600 pixel Image in higher resolution (867 × 658 pixel, file size: 801 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Supernova ... Image File history File links Size of this preview: 790 × 600 pixel Image in higher resolution (867 × 658 pixel, file size: 801 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Supernova ... The Large Magellanic Cloud (LMC) is a nearby satellite galaxy of our own galaxy, the Milky Way. ... For other uses, see NASA (disambiguation). ... A molecular cloud is a type of interstellar cloud whose density and size permits the formation of molecules, most commonly molecular hydrogen (H2). ... This article is about the astronomical term. ...


The kinetic energy of an expanding supernova remnant can trigger star formation due to compression of nearby, dense molecular clouds in space. The increase in turbulent pressure can also prevent star formation if the cloud is unable to lose the excess energy.[76] The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ...


Evidence from daughter products of short-lived radioactive isotopes shows that a nearby supernova helped determine the composition of the Solar System 4.5 billion years ago, and may even have triggered the formation of this system.[77] Supernova production of heavy elements over astronomic periods of time ultimately made the chemistry of life on Earth possible. A radionuclide is an atom with an unstable nucleus. ... This article is about the Solar System. ... Wöhler observes the synthesis of urea. ...


Impact on Earth

A near-Earth supernova is an explosion resulting from the death of a star that occurs close enough to the Earth (roughly fewer than 100 light-years away) to have noticeable effects on its biosphere. Gamma rays are responsible for most of the adverse effects a supernova can have on a living terrestrial planet. In Earth's case, gamma rays induce a chemical reaction in the upper atmosphere, converting molecular nitrogen into nitrogen oxides, depleting the ozone layer enough to expose the surface to harmful solar and cosmic radiation. The gamma ray burst from a nearby supernova explosion has been proposed as the cause of the end Ordovician extinction, which resulted in the death of nearly 60% of the oceanic life on Earth.[78] This article is about the astronomical object. ... A light-year, symbol ly, is the distance light travels in one year: exactly 9. ... For other uses, see Biosphere (disambiguation). ... This article is about electromagnetic radiation. ... The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... For other uses, see Chemical reaction (disambiguation). ... Air redirects here. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... The term nitrogen oxide is a general term and can be used to refer to any of these oxides (oxygen compounds) of nitrogen, or to a mixture of them: Nitric oxide (NO), nitrogen(II) oxide Nitrogen dioxide (NO2) Dinitrogen monoxide (N2O) (Nitrous oxide) Dinitrogen trioxide (N2O3) Dinitrogen tetroxide (N2O4) Dinitrogen... The ozone layer is a layer in Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Solar irradiance spectrum at top of atmosphere. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... The image above shows the optical afterglow of gamma ray burst GRB-990123 taken on January 23, 1999. ... The Ordovician-Silurian extinction event, labeled End O here. ...


Speculation as to the effects of a nearby supernova on Earth often focuses on large stars as Type II supernova candidates. Several prominent stars within a few hundred light years from the Sun are candidates for becoming supernovae in as little as a millennium. One example is Betelgeuse, a red supergiant 427 light-years from Earth.[79] Though spectacular, these "predictable" supernovae are thought to have little potential to affect Earth. This article is about the star. ...


Recent estimates predict that a Type II supernova would have to be closer than eight parsecs (26 light-years) to destroy half of the Earth's ozone layer.[80] Such estimates are mostly concerned with atmospheric modeling and considered only the known radiation flux from SN 1987A, a Type II supernova in the Large Magellanic Cloud. Estimates of the rate of supernova occurrence within 10 parsecs of the Earth vary from once every 100 million years[81] to once every one to ten billion years.[82] A parsec is the distance from the Earth to an astronomical object which has a parallax angle of one arcsecond. ... Beaded ring brightens from 2003 and 2005 SN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a nearby dwarf galaxy. ... The Large Magellanic Cloud (LMC) is a nearby satellite galaxy of our own galaxy, the Milky Way. ...


Type Ia supernovae are thought to be potentially the most dangerous if they occur close enough to the Earth. Because Type Ia supernovae arise from dim, common white dwarf stars, it is likely that a supernova that could affect the Earth will occur unpredictably and take place in a star system that is not well studied. One theory suggests that a Type Ia supernova would have to be closer than a thousand parsecs (3300 light-years) to affect the Earth.[83] The closest known candidate is IK Pegasi (see below).[84] This article or section does not adequately cite its references or sources. ... IK Pegasi (or HR 8210) is a binary star system in the constellation Pegasus. ...


In 1996, astronomers at the University of Illinois at Urbana-Champaign theorized that traces of past supernovae might be detectable on Earth in the form of metal isotope signatures in rock strata. Subsequently, iron-60 enrichment has been reported in deep-sea rock of the Pacific Ocean by researchers from the Technical University of Munich.[85][86][87] A Corner of Main Quad The University of Illinois at Urbana-Champaign (UIUC, U of I, or simply Illinois), is the oldest, largest, and most prestigious campus in the University of Illinois system. ... Interstate road cut through limestone and shale strata in eastern Tennessee In geology and related fields, a stratum (plural: strata) is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... Technische Universität München (TUM) (English: Technical University of Munich) is a German university, part of the Deutsche Forschungsgemeinschaft, a society of Germanys leading research universities in Munich. ...


Milky Way candidates

The nebula around Wolf-Rayet star WR124, which is located at a distance of about 21,000 light years. NASA image.
The nebula around Wolf-Rayet star WR124, which is located at a distance of about 21,000 light years.[88] NASA image.

Several large stars within the Milky Way have been suggested as possible supernovae within the next few thousand to hundred million years. These include Rho Cassiopeiae,[89] Eta Carinae,[90][91] RS Ophiuchi,[92][93] the Kitt Peak Downes star KPD1930+2752,[94] HD 179821,[95][96] IRC+10420,[97] VY Canis Majoris,[98] Betelgeuse, Antares, and Spica.[79] Image File history File links Wolf_rayet2. ... Image File history File links Wolf_rayet2. ... A Wolf-Rayet nebula is a nebula which surrounds a Wolf-Rayet star. ... Hubble Space Telescope image of nebula M1-67 around Wolf Rayet star WR 124 Wolf-Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses), and are losing their mass rapidly by means of a very strong stellar wind, with speeds up to 2000... For other uses, see NASA (disambiguation). ... For other uses, see Milky Way (disambiguation). ... Rho Cassiopeiae (ρ Cas / ρ Cassiopeiae) is a yellow hypergiant in the constellation Cassiopeia. ... Eta Carinae (η Carinae or η Car) is a highly luminous hypergiant double star. ... RS Ophiuchi (RS Oph) is a nova approximately 1,950 light-years away in the constellation Ophiuchus. ... VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation of Canis Major. ... This article is about the star. ... This article or section does not cite its references or sources. ... Spica (α Vir / α Virginis / Alpha Virginis) is the brightest star in the constellation Virgo, and one of the brightest stars in the nighttime sky. ...


Many Wolf-Rayet stars, such as Gamma Velorum,[99] WR 104,[100] and those in the Quintuplet Cluster,[101] are also considered possible precursor stars to a supernova explosion in the 'near' future. Hubble Space Telescope image of nebula M1-67 around Wolf Rayet star WR 124 Wolf-Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses), and are losing their mass rapidly by means of a very strong stellar wind, with speeds up to 2000... Gamma Velorum (γ Vel / γ Velorum) is a star system in the constellation Vela. ...


The nearest supernova candidate is IK Pegasi (HR 8210), located at a distance of only 150 light-years. This closely-orbiting binary star system consists of a main sequence star and a white dwarf, separated by only 31 million km. The dwarf has an estimated mass equal to 1.15 times that of the Sun.[102] It is thought that several million years will pass before the white dwarf can accrete the critical mass required to become a Type Ia supernova.[103][104] IK Pegasi (or HR 8210) is a binary star system in the constellation Pegasus. ... A binary star system consists of two stars both orbiting around their barycenter. ... This article or section does not adequately cite its references or sources. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ...


See also

Remnant of Keplers Supernova, SN 1604 Remnant of Tychos Nova, SN 1572 A supernova remnant (SNR) is the structure resulting from the gigantic explosion of a star in a supernova. ... Cassiopeia A Crab Nebula Gum Nebula SN 1604 SN 1987A Veil Nebula Vela Supernova Remnant W49B See also Supernova remnant Supernova Categories: | | ... A dwarf nova is a type of cataclysmic variable, consisting of a close binary star system in which one of the components is a white dwarf, which accretes matter from its companion. ... Timeline of white dwarfs, neutron stars, and supernovae Note that this list is mainly about the development of knowledge, but also about some supernovae taking place. ... The Champagne Supernova, SN 2003fg (designated SNLS-03D3bb by the Canada-France-Hawaii Supernova Legacy Survey, which discovered it), was an aberrant type Ia supernova discovered in 2003 and described in the journal Nature on September 21 of 2006. ...

Notes

  1. ^  For a core primarily composed of oxygen, neon and magnesium, the collapsing white dwarf will typically form a neutron star. In this case, only a fraction of the star's mass will be ejected during the collapse.[105]
  2. ^  Per the American Physical Society Neutrino Study reference,[50] roughly 99% of the gravitational potential energy is released as neutrinos of all flavors. The remaining 1% is equal to 1044 J

For the story by Larry Niven, see Neutron Star (story). ... The American Physical Society was founded in 1899 and is the worlds second largest organization of physicists. ...

References

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  2. ^ Introduction to Supernova Remnants. NASA Goddard Space Flight Center (July 27, 2006). Retrieved on 2006-09-07.
  3. ^ a b c Mazzali, P. A.; K. Röpke, F. K.; Benetti, S.; Hillebrandt, W. (2007). "A Common Explosion Mechanism for Type Ia Supernovae". Science 315 (5813): 825–828. doi:10.1126/science.1136259. Retrieved on 2007-05-24. 
  4. ^ a b Gilmore, Gerry (2004). "The Short Spectacular Life of a Superstar". Science 304 (5697): 1915–1916. Retrieved on 2007-05-01. 
  5. ^ a b "Integral identifies supernova rate for Milky Way", European Space Agency, January 4, 2006. Retrieved on 2007-02-02. 
  6. ^ Allen, Jesse (February 02, 1998). Supernova Effects. NASA. Retrieved on 2007-02-02.
  7. ^ D. H. Clark, F. R. Stephenson (June 29, 1981). "The Historical Supernovae". Supernovae: A survey of current research; Proceedings of the Advanced Study Institute: 355–370, Cambridge, England: Dordrecht, D. Reidel Publishing Co.. Retrieved on 2006-09-24. 
  8. ^ van Zyl, Jan Eben (2003). VARIABLE STARS VI. Astronomical Society of Southern Africa. Retrieved on 2006-09-27.
  9. ^ B. Leibundgut, J. Sollerman (2001). "A cosmological surprise: the universe accelerates". Europhysics News 32 (4). Retrieved on 2007-02-01. 
  10. ^ "Confirmation of the accelerated expansion of the Universe", Centre National de la Recherche Scientifique, September 19, 2003. Retrieved on 2006-11-03. 
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Artist depiction of the WMAP satellite at the L2 point The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite whose mission is to survey the sky to measure the temperature of the radiant heat left over from the Big Bang. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ... The American Journal of Physics is a peer-reviewed scientific journal published by the American Association of Physics Teachers devoted to the educational and cultural aspects of physics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 225th day of the year (226th in leap years) in the Gregorian calendar. ... is the 24th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... The Max Planck Institute for Gravitational Physics (Albert Einstein Institute) is a Max Planck Institute whose research is aimed at investigating Einstein’s theory of relativity and beyond: Mathematics, quantum gravity, astrophysical relativity, and gravitational wave astronomy. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... Dr. John Gribbin (1946 - ) is a British science writer and a visiting Fellow in astronomy at the University of Sussex. ... Yale University Press is a book publisher founded in 1908. ... is the 302nd day of the year (303rd in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... The American Physical Society was founded in 1899 and is the worlds second largest organization of physicists. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 346th day of the year (347th in leap years) in the Gregorian calendar. ... The Astrophysical Journal is a scientific journal covering astronomy and astrophysics. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... is the 24th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Los Alamos National Laboratory, aerial view from 1995. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 343rd day of the year (344th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... The European Southern Observatory (ESO, also more formally the European Organisation for Astronomical Research in the Southern Hemisphere) is an intergovernmental research organisation for astronomy, composed and supported by twelve countries from the European Union plus Switzerland. ... is the 169th day of the year (170th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 303rd day of the year (304th in leap years) in the Gregorian calendar. ... The Astrophysical Journal is a scientific journal covering astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 221st day of the year (222nd in leap years) in the Gregorian calendar. ... is the 127th day of the year (128th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 144th day of the year (145th in leap years) in the Gregorian calendar. ... Swinburne University of Technology is a university based in a number of campuses in the eastern suburbs of Melbourne, Australia. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... This article is about the British Society. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Astronomy and Astrophysics (often referred to as A&A) is a European Journal, publishing papers on theoretical, observational and instrumental astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... The headquarters of the Cambridge University Press, in Trumpington Street, Cambridge. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... is the 262nd day of the year (263rd in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... For other uses, see NASA (disambiguation). ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 222nd day of the year (223rd in leap years) in the Gregorian calendar. ... The Astrophysical Journal is a scientific journal covering astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... The Astrophysical Journal is a scientific journal covering astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... McDonald Observatorys 2. ... is the 61st day of the year (62nd in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 345th day of the year (346th in leap years) in the Gregorian calendar. ... is the 9th day of the year in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 347th day of the year (348th in leap years) in the Gregorian calendar. ... The European Southern Observatory (ESO, also more formally the European Organisation for Astronomical Research in the Southern Hemisphere) is an intergovernmental research organisation for astronomy, composed and supported by twelve countries from the European Union plus Switzerland. ... is the 218th day of the year (219th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 345th day of the year (346th in leap years) in the Gregorian calendar. ... is the 241st day of the year (242nd in leap years) in the Gregorian calendar. ... is the 255th day of the year (256th in leap years) in the Gregorian calendar. ... Year 1993 (MCMXCIII) was a common year starting on Friday (link will display full 1993 Gregorian calendar). ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 352nd day of the year (353rd in leap years) in the Gregorian calendar. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... The Astrophysical Journal is a scientific journal covering astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... ICARUS is the official journal of the Division for Planetary Sciences of the American Astronomical Society. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... For other uses, see NASA (disambiguation). ... is the 250th day of the year (251st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 170th day of the year (171st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Space. ... Astronomy and Astrophysics (often referred to as A&A) is a European Journal, publishing papers on theoretical, observational and instrumental astronomy and astrophysics. ... is the 141st day of the year (142nd in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 293rd day of the year (294th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... The Harvard-Smithsonian Center for Astrophysics (CfA) is located in Cambridge, Massachusetts. ... is the 214th day of the year (215th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 159th day of the year (160th in leap years) in the Gregorian calendar. ... is the 69th day of the year (70th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Nature is a prominent scientific journal, first published on 4 November 1869. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Nature is a prominent scientific journal, first published on 4 November 1869. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... April 8 is the 98th day of the year (99th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 89th day of the year (90th in leap years) in the Gregorian calendar. ... Sky & Telescope is a monthly magazine providing articles and information on all aspects of astronomy, space exploration, telescope equipment, and amateur telescope making and use. ... A Corner of Main Quad The University of Illinois at Urbana-Champaign (UIUC, U of I, or simply Illinois), is the oldest, largest, and most prestigious campus in the University of Illinois system. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Physical Review Letters is one of the most prestigious journals in physics. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 158th day of the year (159th in leap years) in the Gregorian calendar. ... PPARC is an abbreviation for the Particle Physics and Astronomy Research Council, and is the UKs strategic science investment agency based in Swindon. ... is the 31st day of the year in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 5th day of the year in the Gregorian calendar. ... is the 322nd day of the year (323rd in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... The European Southern Observatory (ESO, also more formally the European Organisation for Astronomical Research in the Southern Hemisphere) is an intergovernmental research organisation for astronomy, composed and supported by twelve countries from the European Union plus Switzerland. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... Space. ... is the 66th day of the year (67th in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 6th day of the year in the Gregorian calendar. ... is the 200th day of the year (201st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Space. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... This article reads like an advertisement. ... is the 206th day of the year (207th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 335th day of the year (336th in leap years) in the Gregorian calendar. ... Space. ... is the 217th day of the year (218th in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 6th day of the year in the Gregorian calendar. ... is the 156th day of the year (157th in leap years) in the Gregorian calendar. ... This article is about the year. ... The American Astronomical Society (AAS) is a US society of professional astronomers and other interested individuals, headquartered in Washington, DC. The main aim of the AAS is provide a political voice for its members and organise their lobbying. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... Astronomy and Astrophysics (often referred to as A&A) is a European Journal, publishing papers on theoretical, observational and instrumental astronomy and astrophysics. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... is the 277th day of the year (278th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... is the 8th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 16th day of the year in the Gregorian calendar. ... A Corner of Main Quad The University of Illinois at Urbana-Champaign (UIUC, U of I, or simply Illinois), is the oldest, largest, and most prestigious campus in the University of Illinois system. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... is the 99th day of the year (100th in leap years) in the Gregorian calendar. ... Events of 2008: (EMILY) Me Lesley and MIley are going to China! This article is about the year. ... The Astronomy Picture of the Day (APOD) website is a service provided by NASA and MTU (Michigan Technological University). ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... is the 247th day of the year (248th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Space. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 8th day of the year in the Gregorian calendar. ... The Astronomical Society of the Pacific (ASP) was founded in San Francisco in 1889. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 32nd day of the year in the Gregorian calendar. ... is the 143rd day of the year (144th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... New Scientist is a weekly international science magazine covering recent developments in science and technology for a general English-speaking audience. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 12th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 12th day of the year in the Gregorian calendar. ... is the 24th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 158th day of the year (159th in leap years) in the Gregorian calendar. ...

Further reading

  • Hans Bethe (September 1990). "SUPERNOVAE. By what mechanism do massive stars explode?" (PDF). Physics Today 43 (9): 24–27. 
  • Takahashi, K.; Sato, K.; Burrows, A.; Thompson, T. A. (2003). "Supernova Neutrinos, Neutrino Oscillations, and the Mass of the Progenitor Star". Physical Review D 68 (11): 77–81. Retrieved on 2006-11-28. —a good review of supernova events.
  • Hillebrandt, Wolfgang; Hans-Thomas Janka and Ewald Müller (October 2006). "How to Blow Up a Star". Scientific American 295 (4): 42–49. 
  • Woosley, Stan; Hans-Thomas Janka (December 2005). "The Physics of Core-Collapse Supernovae" (PDF). Nature Physics 1 (3): 147–154. doi:10.1038/nphys172. —link is to a pre-print of the article submitted to Nature.

Hans Albrecht Bethe (pronounced bay-tuh; July 2, 1906 – March 6, 2005), was a German-American physicist who won the Nobel Prize in Physics in 1967 for his work on the theory of stellar nucleosynthesis. ... Physics Today magazine, created in 1948, is the flagship publication of The American Institute of Physics. ... Ken Croswell is an astronomer and author living in Berkeley, California. ... The Alchemy of the Heavens is a book by Ken Croswell. ... This is the article on the publisher Annual Reviews whose titles are invariably called Annual review of . ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 332nd day of the year (333rd in leap years) in the Gregorian calendar. ... Scientific American is a popular-science magazine, published (first weekly and later monthly) since August 28, 1845, making it the oldest continuously published magazine in the United States. ... October 2005 cover of Nature Physics Nature Physics, published by the Nature Publishing Group, is a scientific journal focusing on pure and applied physics. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Nature is a prominent scientific journal, first published on 4 November 1869. ...

External links

  • List of Supernovae-related Web pages.
  • RSS news feed (RSS). The Astronomer's Telegram. Retrieved on 2006-11-28.
  • D. Yu. Tsvetkov, N. N. Pavlyuk, O. S. Bartunov, Yu. P. Pskovskii. Sternberg Astronomical Institute Supernova Catalogue. Sternberg Astronomical Institute, Moscow University. Retrieved on 2006-11-28.—a searchable catalog.
  • Anonymous (January 18, 2007). BoomCode. WikiUniversity. Retrieved on 2007-03-17.—Boom Code—Professional-grade type II supernova simulator on Wikiversity.
  • List All Supernovae. IAU: Central Bureau for Astronomical Telegrams. Retrieved on 2008-03-24.

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 332nd day of the year (333rd in leap years) in the Gregorian calendar. ... Sternberg Astronomical Institute is a research institution in Moscow, Russia, division of Moscow State University. ... Moscow State University campus M.V. Lomonosov Moscow State University (Московский Государственный Университет имени М.В.Ломоносова, often abbreviated МГУ, MSU, MGU) is considered the oldest university in Russia, founded in 1755. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 332nd day of the year (333rd in leap years) in the Gregorian calendar. ... is the 18th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a sister project to Wikipedia and is part of the Wikimedia foundation, begun on July 10, 2003. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 83rd day of the year (84th in leap years) in the Gregorian calendar. ...


  Results from FactBites:
 
Supernova - Wikipedia, the free encyclopedia (3829 words)
Supernovae are the main source of all the elements heavier than oxygen.
Supernovae generate tremendous temperatures, and under the right conditions, the fusion reactions that take place during the peak moments of a supernova can produce some of the heaviest elements, such as plutonium and californium.
For Type II supernovae, the core collapse is eventually halted by degeneracy pressure of neutrons, at a density comparable to that of an atomic nucleus (forming a neutron star).
  More results at FactBites »

 
 

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