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SN 1987A

Circumstellar rings around SN 1987A, with the ejecta from the supernova explosion at the center of the inner ring.
Observation data (Epoch J2000.0)
Supernova typeType II-P (unusual)
Remnant typeunknown
Host GalaxyLarge Magellanic Cloud (LMC)
ConstellationDorado
Right ascension05h 35m 28. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. A supernova (plural supernovae or supernovas) is a stellar Explosion. A supernova (plural supernovae or supernovas) is a stellar Explosion. A supernova remnant ( SNR) is the structure resulting from the gigantic explosion of a Star in a Supernova. A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter The Large Magellanic Cloud (LMC is a nearby Satellite galaxy of our own galaxy the Milky Way. In common usage a constellation is a group of celestial bodies that are connected together in some arrangement typically stars to form a visible figure or picture Dorado (dɒˈrɑːdoʊ Mahi-mahi or dolphin-fish is a southern Constellation. Right ascension (abbrev RA; symbol α) is the Astronomical term for one of the two Coordinates of a point on the Celestial sphere 03s (J2000) [1]
Declination−69° 16′ 11. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either 79″ (J2000) [1]
Galactic coordinatesunknown
Discovery Date24 February 1987 (23:00 UTC) [2]
Peak magnitude (V)+3
Distance168,000 light-years, or 51. The galactic coordinate system is a Celestial coordinate system which is centered on the Sun and is aligned with the apparent center of the Milky Way galaxy Events 303 - Galerius, Roman Emperor, publishes his edict that begins the persecution of Christians in his portion of the Year 1987 ( MCMLXXXVII) was a Common year starting on Thursday (link displays 1987 Gregorian calendar) The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value 4 kpc
Physical characteristics
ProgenitorSanduleak -69° 202a
Progenitor typeB3 supergiant
Colour (B-V)+0. History The first direct measurements of an object at interstellar distances were undertaken by German Astronomer Friedrich Wilhelm Bessel in 1838 Sanduleak -69° 202a was a magnitude 12 Blue supergiant Star, located on the outskirts of the Tarantula Nebula in the Large Magellanic Cloud. 085
Notable featuresClosest recorded supernova
since invention of telescope
A time sequence of Hubble Space Telescope images, showing the collision of the expanding supernova remnant with a ring of dense material ejected by the progenitor star 20,000 years before the supernova.
A time sequence of Hubble Space Telescope images, showing the collision of the expanding supernova remnant with a ring of dense material ejected by the progenitor star 20,000 years before the supernova. A supernova remnant ( SNR) is the structure resulting from the gigantic explosion of a Star in a Supernova.
AAVSO light curve of 2,589 visual observations of SN 1987A from Jan 1, 1987 - Jan 1, 1990. Up is brighter and down is fainter.
AAVSO light curve of 2,589 visual observations of SN 1987A from Jan 1, 1987 - Jan 1, 1990. Since its founding in 1911 the American Association of Variable Star Observers (AAVSO has coordinated collected evaluated analyzed published and archived Variable star In Astronomy, a light curve is a graph of light intensity of a Celestial object or region as a function of time Up is brighter and down is fainter.

SN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a nearby dwarf galaxy. A supernova (plural supernovae or supernovas) is a stellar Explosion. The Tarantula Nebula (also known as 30 Doradus, or NGC 2070) is an H II region in the Large Magellanic Cloud. The Large Magellanic Cloud (LMC is a nearby Satellite galaxy of our own galaxy the Milky Way. A dwarf galaxy is a small Galaxy composed of up to several billion Stars a small number compared to our own Milky Way 's 200-400 billion stars It occurred approximately 51. 4 kiloparsecs from Earth [1], close enough that it was visible to the naked eye. History The first direct measurements of an object at interstellar distances were undertaken by German Astronomer Friedrich Wilhelm Bessel in 1838 EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The naked eye is a Figure of speech referring to human Visual perception that is unaided by enhancing equipment such as a Telescope or It could be seen from the Southern Hemisphere. It was the closest observed supernova since SN 1604, which occurred in the Milky Way itself. Supernova 1604, also known as Kepler's Supernova, Kepler's Nova or Kepler's Star, was a Supernova which occurred in the Milky Way, The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply The light from the supernova reached Earth on February 23, 1987. Events 1455 - Traditional date for the publication of the Gutenberg Bible, the first Western Book printed from Movable Year 1987 ( MCMLXXXVII) was a Common year starting on Thursday (link displays 1987 Gregorian calendar) As the first supernova discovered in 1987, it was labeled "1987A". Its brightness peaked in May with an apparent magnitude of about 3 and slowly declined in the following months. The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value It was the first opportunity for modern astronomers to see a supernova up close. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study

It was discovered by Ian Shelton and Oscar Duhalde at the Las Campanas Observatory in Chile on February 24, 1987, and independently by Albert Jones in New Zealand, and Colin Henshaw (member of the Manchester Astronomical Society) in Zimbabwe. Ian Shelton is a Canadian Astronomer who graduated from the University of Toronto. Las Campanas Observatory is an astronomical Observatory owned and operated by the Carnegie Institution for Science. Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the Events 303 - Galerius, Roman Emperor, publishes his edict that begins the persecution of Christians in his portion of the Year 1987 ( MCMLXXXVII) was a Common year starting on Thursday (link displays 1987 Gregorian calendar) Albert F A L Jones (born 9 August 1920) is a New Zealand amateur astronomer, and a prolific Variable star and Comet New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island See also Great Zimbabwe National Monument. For information about the March and June 2008 presidential elections see Zimbabwean presidential election [2] On March 4-12, 1987 it was observed from space by Astron, the largest ultraviolet space telescope of that time. Astron was a Soviet astrophysical spacecraft launched on March 23 1983 at 124506 UTC by Proton launcher. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays [3]

Since 51. 4 kiloparsecs is approximately 168,000 light-years, the cosmic event itself happened approximately 168,000 years prior to its observation in 1987. A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by

Contents

Precursor

Soon after the event was recorded, the progenitor star was identified as Sanduleak -69° 202a, a blue supergiant. Sanduleak -69° 202a was a magnitude 12 Blue supergiant Star, located on the outskirts of the Tarantula Nebula in the Large Magellanic Cloud. Blue supergiants ( BSG s are Supergiant Stars ( luminosity class I) of spectral type O or B This was an unexpected identification, because at the time a blue supergiant was not considered a possibility for a supernova event in existing models of high mass stellar evolution. Stellar evolution is the process by which a Star undergoes a sequence of radical changes during its lifetime Current understanding is that the progenitor was a binary system, the stars of which merged about 20,000 years before the explosion, producing a blue supergiant. A binary star is a Star system consisting of two Stars orbiting around their Center of mass. Difficulties persist with this interpretation. [4]

Neutrino emissions

Approximately three hours before the visible light from SN 1987A reached the Earth, a burst of neutrinos was observed at three separate neutrino observatories. Neutrinos are Elementary particles that travel close to the Speed of light, lack an Electric charge, are able to pass through ordinary matter almost A neutrino detector is a device designed to detect Neutrinos Because neutrinos are very weakly interacting neutrino detectors must be very large in order to detect a significant This is due to the neutrino emission (which occurs simultaneously with core collapse) preceding the emission of visible light (which occurs only after the shock wave reaches the stellar surface). At 7:35am Universal time, Kamiokande II detected 11 antineutrinos, IMB 8 antineutrinos and Baksan 5 neutrinos, in a burst lasting less than 13 seconds. The is a Neutrino Physics Laboratory located underground in the Mozumi Mine of the Kamioka Mining and Smelting Co In Physics, antineutrinos, the Antiparticles of Neutrinos are neutral particles produced in nuclear Beta decay. IMB, the Irvine-Michigan-Brookhaven detector was a Nucleon decay experiment and Neutrino Observatory located in a salt mine on the shore of Lake Erie The Baksan Neutrino Observatory ( BNO) is a Neutrino observatory of INR RAS located in the Baksan gorge in the Caucasus. Water-based instruments detect only antineutrinos of thermal origin[5], while a gallium-71-based instrument detects only neutrinos (lepton number = 1) of either thermal or electron-capture origin. Gallium (ˈgæliəm is a Chemical element that has the symbol Ga and Atomic number 31 In High energy physics, the lepton number is the number of Leptons minus the number of antileptons

Although the actual neutrino count was only 24, it was a significant rise from the previously-observed background level. This was the first time neutrinos emitted from a supernova had been observed directly, and the observations were consistent with theoretical supernova models in which 99% of the energy of the collapse is radiated away in neutrinos. The observations are also consistent with the models' estimates of a total neutrino count of 1058 with a total energy of 1046 joules.

One highly significant result was obtained from the data regarding gravity. It appeared that the neutrinos and antineutrinos both took the same amount of time to arrive at earth, about 168,000 years. In Physics, antineutrinos, the Antiparticles of Neutrinos are neutral particles produced in nuclear Beta decay. The difference in their arrival times was less than 12 seconds. This was the first empirical evidence that matter, antimatter, and photons all react similarly to gravity, which had been widely predicted by standard theories of gravity but had not been previously shown from direct empirical data. In Particle physics and Quantum chemistry, antimatter is the extension of the concept of the Antiparticle to Matter, where antimatter is composed In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena Gravitation is a natural Phenomenon by which objects with Mass attract one another

Missing neutron star?

SN 1987A appears to be a core-collapse supernova, which should result in a neutron star. A neutron star is a type of remnant that can result from the Gravitational collapse of a massive Star during a Type II, Type Ib or Type Since the supernova first became visible, astronomers have been searching for the collapsed core but have not detected it. The Hubble Space Telescope took the sharpest images of the supernova to date. The Hubble Space Telescope ( HST; also known colloquially as "the Hubble" or just "Hubble" is a space telescope that was carried into The images show no evidence of a neutron star. Two possibilities for the 'missing' neutron star are being considered. The first is that the neutron star is enshrouded in dense dust clouds so that it cannot be seen. The second is that large amounts of material fell back on the neutron star, so that it further collapsed into a black hole. A black hole is a theoretical region of space in which the Gravitational field is so powerful that nothing not even Electromagnetic radiation (e

SN1987A distance and the speed of light

The three bright rings around SN 1987A are material from the stellar wind of the progenitor. These rings were ionized by the ultraviolet flash from the supernova explosion, and consequently began emitting in various emission lines. These rings did not "turn on" until several months after the supernova, and the turn-on process can be very accurately studied through spectroscopy. The rings are large enough for their angular size to be measured accurately: the inner ring is 0. 808 arcseconds in radius. Using the distance light must have traveled to light up the inner ring as the base of a right angle triangle, and the angular size as seen from the Earth for the local angle, one can use basic trigonometry to calculate the distance to SN1987A, which is about 168,000 light-years. [6]

See also

References

  1. ^ a b c SN1987A in the Large Magellanic Cloud. See also Supernova remnant Supernova Hubble Heritage Project. The Hubble Heritage Project was founded by a group of astronomers in 1998 Retrieved on 2006-07-25. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 285 - Diocletian appoints Maximian as Caesar, co-ruler
  2. ^ a b IAUC4316: 1987A, N. Cen. 1986 (24 February 1987). Events 303 - Galerius, Roman Emperor, publishes his edict that begins the persecution of Christians in his portion of the Year 1987 ( MCMLXXXVII) was a Common year starting on Thursday (link displays 1987 Gregorian calendar)
  3. ^ Observations on Astron: Supernova 1987A in the Large Magellanic Cloud
  4. ^ Galactic Twins of the Nebula Around SN 1987A: Hints that LBVs may be supernova May 2007
  5. ^ Mann, Alfred K. (1997). Shadow of a star: The neutrino story of Supernova 1987A. New York: W. H. Freeman, page 127. ISBN 0716730979.  
  6. ^ Panagia, N. . "New Distance Determination to the LMC". Memorie della Societa Astronomia Italiana 69: 225.  
The expanding supernova remnant around Supernova 1987A and its interaction with its surroundings, seen in X-ray and visible light.
The expanding supernova remnant around Supernova 1987A and its interaction with its surroundings, seen in X-ray and visible light. The arXiv ( pronounced " Archive " as if the "X" were the Greek letter Chi, χ is an Archive for electronic A supernova remnant ( SNR) is the structure resulting from the gigantic explosion of a Star in a Supernova.

External links

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