Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 21, Problem 11Q
To determine
The year in which the Earth observers would have seen the supernova explosion that formed the Crab Nebula.
To determine
(b)
Whether or not, answer of part (a) agrees with the known year of supernova, 1054 C.E. Reason for discrepancies (if any).
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International Astronomical Union reported on 24 Feb 1987:
An object was discovered on Feb. 24.37 UT (position R.A. = 5h35m.8, Decl. = -69
18'), obtained m = 4.8 on Feb. 24.454 UT. This object proved to be the most famous
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It is classified as a SN of the type Il in the Large Magellanic Cloud (SN1987A). Its
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Consider the image above of the Cassiopeia A (Cas A) supernova remnant. The supernova explosion that caused this remnant was observed on earth about 300 years ago. It is about 3000 pc away. Since that time, the shockwave from the supernova has expanded to form the roughly spherical cloud pictured above. From the center point to the edge of the cloud is about 3 pc. Compute the angular diameter of the Cas A supernova remnant as viewed from Earth. Express your answer in arcminutes.
An astronomical image shows two objects that have the same apparent magnitude, i.e., the same brightness. However, spectroscopic follow up observations indicate that while one is a star that is within our galaxy, at a distance dgal away, and has the same luminosity as the Sun, the other is a quasar and has 100x the luminosity of the entire Milky Way galaxy. What is the distance to the quasar? (You may assume, for this rough calculation, that the Milky Way has 1011 stars and that they all have the luminosity as the Sun.) Give your response in Mpc. Value: dgal = 49 pc
Chapter 21 Solutions
Universe: Stars And Galaxies
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