Crab nebula supernova

In 1919 Landmark estimated the distance to the Andromeda galaxy at some 700000 light-years. (Current estimates put it at 2 million light-years.) It was clear that Hartwig s star was a thousand times brighter than any known nova. It was the same Landmark who suggested a connection between the supernova observed by Chinese astronomers in 1054 (the year of the religious schism) and the Crab nebula. 

The shock wave of fresh debris from a supernova explosion travels a great distance. For example, it has been calculated that the Crab Nebula will attain a diameter of 70 light years 23,000 years from now 140 light years in 260,000 years 210 light years in 1.3 million years and 280 light years in 4 million years. After that the expanding shell will begin to dissipate because the velocity of expansion drops to about 1-2 miles/sec. (3,600-7,200 miles/hr.), which is the velocity of the molecules of interstellar gas. 

The Crab Nebula is the most noticeable object in our Galaxy, and the remnant of the famous Chinese guest star appeared in 1054AD, the best association between supernova remnants(SNR) and ancient guest stars. Before seventies, the Crab Nebula was considered as a special SNR with different morphology and physical features from that of most SNRs, Now more and more Crab-like SNRs have been detected(Weiler 1985). It is necessary to make a systematical investigation for the Crab-like SNRs, especially for those with central pulsars because they offer us more physical messages than others. 

Weiler, K.W., 1985, in The Crab Nebula and Related Supernova Remnants, Kafatos, M.and Henry, R. Ed. (Cambridge Univ. Press, London)... 

FIGURE 1 Aristotle s Four Elements and Their Qualities. Aristotle hypothesized that the four basic elements arose from the initial chaos under the influence of four fundamental qualities of matter hot, cold, wet, and dry. The central image representing the initial chaos is taken from a United States National Aeronautics and Space Administration (NASA) photograph of the heart of the Crab Nebula, as viewed by the Hubble Telescope in 1995. The Crab Nebula was first viewed from earth in the year 1054, as recorded by Chinese astronomers. Rock paintings by Native Americans show that they also observed its appearance. Actually, the Crab Nebula was a giant star that exploded as a supernova. The variations in color are caused by chemical elements, created during the life and the explosion of the star. Modern-day astronomers believe that the chemical elements in the earth and in our bodies were made by the explosion of stars billions of years ago. Earth. A Air. A Fire. Water. (D.N.Sherwood)... 

Another, linearly polarized, radio source in the Crab nebula, where a supernova explosion was observed in the year 1054, leaving behind a pulsating neutron star, could be of similar origin as the radiation in the Milky Way. The likelihood that the pulsar drives the acceleration of both relativistic electrons and of cosmic rays could imply that most cosmic rays in the Galaxy are also... 

The ultimate fate of the star following a supernova depends on the exact conditions. A neutron sUir is a very dense and extremely hot star that is composed entirely of neutrons and which is prevented from undergoing further collapse by the Pauli exclusion principle, which states that no two neutrons can have the same exact quantum state. Because of a neutron star s enormous density, it has an extremely large gravitational pull. The massive star that s at the center of the Crab nebula, whose explosion was observed by the Chinese in 1054 AD, is an example of a rapidly rotating neutron star known as a pulsar. A pulsar emits electromagnetic radiation as it... 

As long as the core left behind the supernova explosion is less than about three solar masses, the collapse will be stopped by the pressure of degenerate neutrons. Thus a neutron star is formed which is a very compact object with a radius of only 10 km. Pulsars are rapidly rotating neutron stars. A famous example of a supernova remnant is the Crab nebula. The shell of this nebula expands at velocities of up to 1500 km/s. The filaments contain anomalously high abundances of helium and other more massive chemical elements. The Crab Pulsar rotates 30 times a second (see Fig. 8.9). The Crab Pulsar (PSR B0531-I-21) is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054 and it was observed e.g. by ancient Chinese astronomers. 

It was Walter Baade who made the connection between the historical supernovae and the observed emission nebulae at their positions, thus identifying the remnants of the explosions. The most prominent object is of course the Crab Nebular (Messier 1), the leftover from the supernova in 1054 Baade 1942 May all Oort 1942. With extensive observations of bright supernovae Minkowski Minkowski 1941 introduced two subclasses. Zwicky Zwicky 1965 refined the classification scheme for supemovae further. However, for several decades only two main classes were maintained until in the early eighties it became clear that at least one further subclass needs to be added. 

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