Summary The student will use CCD images of the Crab Nebula and a Hubble Space Te

Question

Summary The student will use CCD images of the Crab Nebula and a Hubble Space Telescope image of SN 1987a to examine a number of characteristics of supernovae and their remnants Background and Theory Supernova explosions are the most powerful events in the universe. In less than a second about 1044 joules of energy are released about the same as the Sun has released in its entire lifetime! The explosion results from the death of a massive star which has consumed its entire fuel supply. The apparent magnitude of a supernova brightens by about 10 magnitudes within a few hours, and for a few months the luminosity of the star is comparable to the luminosity of the entire parent ga Supernovae are rare events, occurring only once or twice per century in a typical galaxy There have been just six supernovae seen in the Milky Way in recorded history, with the most recent occurring in 1604, just before the advent of telescopes The perceptive reader will notice that this rate is much less than the rate of one or two per century reported above (which gives ~20-40 in 2000 years). At visible wavelengths, we cannot see very far into the disk of our galaxy due to light extinction by dust. Therefore, a supernova must be quite close (within ~4 parsecs to be observed. The 1-2 per century rate is based on average detection rates in galaxies other than our own in which we can see the galactic disk face-on with little M1. Crab Nebula extinction Supernovae are classified into two broad categories, based on their light curves (brightness vs. time). Type I supernovae rise sharply to a maximum, and decay gradually, whereas Type II supernovae rise and decay more gradually. Type II can be sub divided into IIL line decay) and IIP (plateau decay). The figure below is a sketch of the three types of light curves ar Type I Type IIP ype IIL Time The spectra of the two main types of supernovae also differ. Type II spectra show mostly hydrogen lines, while Type I spectra have lines of many elements. The progenitor star of a Type I supernova is thought to be a Population II white dwarf in a binary system with a red giant companion. Mass from the red giant accretes onto the white dwarf until the dwarfs mass passes the Chandrasekhar limit of 1.44 solar masses. The dwarf then collapses violently and becomes a Type I supernova. The progenitor star for a Type II supernova is thought to be a Population I massive red (or blue) supergiant. After the star ceases nuclear fusion, gravity takes over and compresses the star to a very small diameter. This implosion causes a shock which bounces off the core, resulting in an explosion which we see as a Type II supernova. The shock carries ofa large fraction of the stellar atmosphere at speeds of 13,000- 30,000 km/s

Explanation / Answer

solving first 3 part

1) average diameter=(308.58 + 225.21)/2=266.895 pixel

2) a=1.2*266.895=320.274 arc second

3)d=320.274*2000/206265=3.105 parsec

d=9.6*10^13 km

d=6.4*10^5 AU

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