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Examines dying stars, causes, effects, theories, example (SNV 1987A).... More...
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Paper Abstract:
Examines dying stars, causes, effects, theories, example (SNV 1987A).
Paper Introduction:
The purpose of this research is to examine the phenomenon of supernovae. The plan of the research will be to set forth the context in which supernova observation and study have emerged in recent years, and then to discuss difficulties associated with supernova definition, study, and understanding, with reference to studies that have been undertaken regarding supernovas in general and the supernova known as SNV 1987A in particular.
On February 23, 1987, a truly cosmic event occurred--or more exactly was found to have occurred. Telescopes in New Zealand and Chile observed what was called the "brightest and closest" supernova to earth since "Kepler's supernova" in 1604 (Rensberger A7; Cowen 120). This was front-page news because telescopes had witnessed the event (marked by uncommon brightness), the historic proximity of the event to earth, and the fact that the initial obser
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"Ring Around 1987 Supernova Provides a New Yardstick." Physics Today 44 (February 1991): 2 .Whitelock, P., Menzies, J., and Caldwell, J.A.R. Indeed, as early as 1992, the luminosity of SNV 1987A was said toresult mainly from half-life decay of cobalt in the explosion (Chevalier629). What is actually observed about the supernova are propertiesassociated with any explosion--the creation of wind, dust clouds, chemicalreactions, and so on. . A., Wagner, R. "Minutes Timescale Search for a Pulsar IN SNR-1987-A." Astronomy and Astrophysics, October 1997: 1 66- 1 68.Rensberger, Boyce. Thedistinctiveness of observations appears to reflect physiochemical changesassociated with nuclear explosive force on one hand and dissipation on theother, with both force and dissipation being features of any stellar lifecycle. The spectrum calculations of Gehrz,et al., measured the formation, composition, and velocity of chemicallydiscrete shells (rings) of dust condensations that were emitted from themass within the first two years of the explosion of Supernova 1987A. Cosmos. However, the fact that in February 1987 aburst of neutrino radiation was recorded by underground detectors tended toconfirm the theory of ultracollapse as the principal precursor feature ofsupernova explosion (Cowen 12 ; Grifols 386). . M., Harrison, T. "Neutrino Radiation From Supernovae." Nuclear Instruments & Methods in Physics Research, 15 April 1992 386-389.Meisner, Richard. The scale of supernova activity--leaving aside fact that the affectedstar is at least eight times bigger than the sun--vis-à-vis explosiveactivity (whether nuclear or not) on earth is suggested by the fact that bydefinition a supernova creates an explosion that is millions of timesbrighter than the sun, the star physically closest to earth. This speculationappears to be a minority view within the scientific community. perhaps into a mathematical point with no dimensions at all. On February 23, 1987, a truly cosmic event occurred--or more exactlywas found to have occurred. A usefulexplanation of the Big Bang is offered by Sagan: All the matter and energy now in the universe was concentrated at extremely high density-a kind of cosmic egg . For example, it has beennoted that the model for supernovae is that they derive from a single-starconfiguration that collapses into itself. The arguments made for radiation as acause of luminosity versus the case made for explosive force is a case inpoint. 671; also Sagan 93), are essential. The supernova phenomenonappears to occur toward the endpoint of nucleosynthesis, or the multiplenuclear reactions that make up the life of a star. The variety of agreement about SNV 1987a should not diminish evidenceof certain disagreements about stellar behavior. According to both Chevalier and Whitelock, et al., the radioactivedecay, chiefly of titanium and secondarily of two forms of cobalt, hasaccounted for luminosity after ten out-years of SNV 1987A observation. However, the Type I binary modelappears to have its advocates. "Effects of Accretion Onto Massive Main-Sequence Stars." Astronomy and Astrophysics 297 (May 1995): 483-493.Chevalier, Roger A. Hence theorganized behavior of cosmic forces, however limited the understanding ofspecific details of that behavior may be, tends also to be confirmed. Perhaps so, but it is thebeauty and perplexity of physiochemical asymmetry rather than symmetry. Cowen summarizes supernova behavior theory: [W]hen an aging star more massive than eight suns finally succumbs to gravity, its core implodes and a shock wave racing out from the collapsed interior ejects the star's outer layers. Theydo not make a specific case for SNV 1987A as a Type I; however, they dosuggest that the possibility of such an interaction would mean thatdiscovery of a binary configuration with the chemical composition of TypeII and not Type I stars would not be a complete surprise. . Writing in 1997, Chevalier attributes highluminosity of SNV 1987A for the first 2 days after discovery to the forceof the explosion itself, or what he calls the "shock heating of theenvelope, but radioactivity subsequently became the dominant power source"(1376). As Chevalier explains (1374), Type II supernovae "have massivestar progenitors [and] . J., Woodward, C. "SN 1987A--The Light- Curve." Proceedings, Astronomical Society of Australia 9 (1991): 1 5- 1 6. Finally, there is the fact that the verysupernova phenomenon is embedded with transformation and evolution. In that titanic cosmic explosion, the universe began an expansion which has never ceased (Sagan 246).The supernova phenomenon duplicates the form of the Big Bang but on asmaller cosmic scale, with a star's (remaining) matter, energy, and spacecompressed to a very small volume until the force of the fusion creates agreat explosion, or inflation. It does notseem reasonable to expect that a given supernova will evolve toward black-hole status in precisely the same way that any other given supernova doesso. To begin with, supernovae are classified as Type I orType II. The fact that dying stars even of the same type do not all behave inthe same way is also problematic. are associated with regions of massive starformation." Type II supernovae form when the dying star's gravity collapsesinto its great massive iron core. In thisregard, Chevalier (1374) cites the "high intrinsic luminosity (about abillion times that of the sun for tens of days)" of SNV 1987A. Type I dying stars, called novae, arebinary, which means they involve complex interaction--mainly gravitationalpull--between two companion stars, the larger and more diffuse of whichcollapses into the smaller and more compressed, called a white dwarf (Sagan233; Braun and Langer 483f). and Langer, N. Nucleosynthesis is alsoassociated with the Big Bang theory of the formation of the universe, i.e.,a massive nuclear explosion of stellar material whose consequence was theformation of a chemically and then biologically diverse cosmos. This fine-tuningproblem is regarded by many as the biggest remaining difficulty with theinflationary model" of both Universe and supernovae. "A Supernova Turns 1 ." Science News, 22 February 1997: 12 - 121.Deloore, C., and Vanbeveren, D. D., Jones, T. One view is that they form black holes, i.e., compress further,absorbing cosmic matter and space and gravity instead of distributing anddiffusing through space. "The Peculiar Infrared Temporal Development Of Nova Vulpeculae 1987." Astrophysical Journal 4 , 1 December 1992: 671-68 .Grifols, J.A. An"optically thick" or condensed carbon dust shell of early appearance andgreat velocity was followed by a zone of dust comprising oxygen-embeddedsilicates of greater gaseousness and lesser velocity, all of which isconsistent with massive explosion and emissions, which the study concludedwas consistent with dust-shell condensation and formation of other so-called dusty novae, as well as with solar emissions behavior. "And Still There Is No Pulsar." Nature, 17 December 1992: 628-9.---. "Supernova Stabilizes Puzzlingly." The Washington Post, 5 March 1987: A4.Sagan, Carl. However, it is misleading to conceptualize theobservation as something as visible as, say, the explosion of a building.Telescopes, as well as electromagnetic spectrum instrumentation, whichmeasures wavelengths of light, and which identifies the "spectralsignatures" of elemental/chemical behavior in the supernova environment(Gehrz, et al. Telescopes in New Zealand and Chile observedwhat was called the "brightest and closest" supernova to earth since"Kepler's supernova" in 16 4 (Rensberger A7; Cowen 12 ). In this connection, Deloore and Van Beverensuggest (274ff) the possibility of what they term a "close binary" originfor SNV 1987A, based on a rather technical analysis of apparent interactionbetween helium and hydrogen (the latter a component of Type I stars). One reasonthe supernovae that have been discovered are not visible to the naked eyesis that their physical location is in galaxies that are tens of millions oflight years away from earth (Chevalier 1374). There are differences in the urgency, intensity, and rapidityof explosion activity observed according as observations are made days,weeks, months, or years after the first detection of the event. passim). One feature of SNV 1987A observation that still does not appear tohave been resolved once for all is the variety of reported reasons forconclusions drawn from observations. E., Hayward, T. SNV 1987A is a Type II supernova, i.e.,originated as one great star. The remaining core, which is so dense that protons and electrons are pushed together, is known as a neutron star (Cowen 12 ).The entire star matter of a neutron star is ultracompressed neutron atomicparticles. Supernovae and Nucleosynthesis: An Investigation of the History of Matter, from the Big Bang to the Present. The purpose of this research is to examine the phenomenon ofsupernovae. As of 1997,SNV 1987A does not appear to have developed a pulsar, although measurementsindicate that a neutron star was formed. Chevalier ("Still" 629) attributesthe activity around SNV 1987A to the physical consequences of the explosionitself and speculates that the absence of a pulsar is positive evidence ofthe formation of a black hole. The plan of the research will be to set forth the context inwhich supernova observation and study have emerged in recent years, andthen to discuss difficulties associated with supernova definition, study,and understanding, with reference to studies that have been undertakenregarding supernovas in general and the supernova known as SNV 1987A inparticular. Supernovae do appear to mimic the behavior of the Big Bang, exceptthat the ultimate consequence of supernova activity is compression and notexpansion. Is the behavior of stars beautiful to watch? Such instruments allow the amountand composition of chemicals, as well as the ambient temperature behaviorof supernovae, to be calculated. The detritus of such explosions, unlike theoriginal Big Bang, has a place to go: outer space. In particular, theHubble Telescope made possible the discovery of a variety of rings aroundSNV 1987A, which appear to be composed of chemical dust clouds(Schwarzschild 2 ; Gehrz, et al. The core of the neutron star, which emits regular radio waves,is a pulsar (Sagan 239; Narita, Ogelman, and Gouiffes, 1 66). The chemical composition of SNV1987A also altered over time. Just how they go there,however, like the Big Bang theory itself, is a matter of scientificdispute, or more exactly a lack of consensus, owing to the difficultiesassociated with making conclusions as a result of cosmic observations. This was front-page news because telescopes had witnessed the event (marked by uncommonbrightness), the historic proximity of the event to earth, and the factthat the initial observation occurred in the Southern hemisphere. One difficulty with making calculations and with drawing conclusionsbased on observation and calculation is that there is not one uniformsupernova category. Asstriking as SNV 1987A was, it was not unique in astronomy history. For example, citing the almost miraculous fine-tuning that the Big Bang theory implies must have occurred to form thecosmos, Meisner (82) says that the moment between the supposed instantrecollapse and instant inflation of the Big Bang "is infinitesimal,requiring fine-tuning to within one part in 1 15 when the Universe was onesecond old, and one part in 1 6 at the moment of creation. E., Greenhouse, M. "Astronomers Discover the Dying Glow of a Massive Star." The Washington Post, 25 February 1987, A7.---. "A Binary Evolutionary Model for the Progenitor of SN-1987-A." Astronomy and Astrophysics 26 (July 1992): 273-282.Gehrz, R. . What cameto be called Supernova 1987 A (SNV 1987A) has been under observation eversince, not only in Chile and New Zealand but in outer space itself. A simple definition of a supernova is that it is a dying star, or onewhose gravity is starting to collapse, that undergoes a massive,ultrabright nuclear explosion of energy before disappearing altogether(Arnett, 75ff et passim)--whether to form an ultracollapsed neutron star orso-called black hole, or to somehow simply dissipate in the universe doesnot appear to be precisely known. Works CitedArnett, David. [T]he entire universe, matter and energy and the space they fill, occupied a very small volume. However, some four years later, that measurement wasrecalculated, so that over the entire period the explosion was seen to havehad an average velocity of 35, km/s, "after which the velocity slowed byan order of magnitude" (Chevalier 1375). Toobserve supernova phenomena is to watch the cosmically gradual burst ofextraordinary life, to be followed by the death, of a star. "Type II Supernovae SN 1987A and SN 1993J." Science, 3 May 1997: 1374- 1378.Cowen, Ron. . New York: Random House, 198 .Schwarzschild, Bertram. L., Benson, J. For example, in the days following the first discovery of SNV 1987A,the velocity of initial explosive force was measured at 4 , kilometersper second. "Cosmological Darwinism." Analog Science Fiction/Science Fact, 117 (November 1997): 82-92.Narita, T., Ogelman, H., and Gouiffes, C. In 1572 and 16 6, TychoBrahe and Johannes Kepler, respectively, made the first and only Europeantelescopic observations of supernova activity in the Milky Way (Sagan 237).SNV 1987A was discovered in the Large Magellanic Cloud, a satellite galaxyof the Milky Way (Sagan 237; Rensenberger A4). . Such calculations, in turn, are meant toexplain or pinpoint the state of life of a given supernova and to forecastpossible lines of future development. In theNorthern hemisphere in 1 54, Chinese astronomers described a "guest star"in Taurus, and Anasazi in the American Southwest created a pictograph ofthe same star, which was eventually to be identified as the Crab Supernova,the progenitor of the still observable Crab Nebula. Princeton: Princeton U P, 1996.Braun, H. . Cowen (12 ) cites the view that it possiblyhad aged to the size of a red giant, then collapsed into a smaller bluegiant before inflating to supernova status Time is another factor that contributes to the difficulty of studyingsupernovae.
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