Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Question
Chapter 17, Problem 25Q
To determine
(a)
The absolute magnitude of the given star.
To determine
(b)
The approximate ratio of luminosity of the given star to the Sun’s luminosity.
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A star has a parallax angle of 0.0270 arcseconds and an apparent magnitude of 4.641. The distance to this star is 37.03 parsecs and the absolute magintude is 1.79.
18: What is the luminosity of this star? (HINT: The luminosity of the Sun is 3.85×1026 W.) Using the Forumla M1 - M2 = -2.5 log(L1/L2)
the absolute magnitude of the Sun is 4.8
An O8 V star has an apparent visual magnitude of +5. Use the method of spectroscopic parallax to estimate the distance to the star (in pc). (Hints: Refer to one of the H–R diagrams in the chapter, and use the magnitude–distance formula,
d = 10(mV − MV + 5)/5
where d is the distance in parsecs, mV and MV are the apparent and absolute visual magnitude respectively.)
"51 Pegasi" is the name of the first normal star (besides the Sun) around which a planet was discovered. It is in the constellation Pegasus the horse. Its parallax is measured to be 0.064 arcsec.
a. What is its distance from us?
b. The apparent brightness is 1.79 × 10-10 J/(s·m2 ). What is the luminosity? How does that compare with that of the Sun? Look up the temperature: how do
Chapter 17 Solutions
Universe: Stars And Galaxies
Ch. 17 - Prob. 1QCh. 17 - Prob. 2QCh. 17 - Prob. 3QCh. 17 - Prob. 4QCh. 17 - Prob. 5QCh. 17 - Prob. 6QCh. 17 - Prob. 7QCh. 17 - Prob. 8QCh. 17 - Prob. 9QCh. 17 - Prob. 10Q
Ch. 17 - Prob. 11QCh. 17 - Prob. 12QCh. 17 - Prob. 13QCh. 17 - Prob. 14QCh. 17 - Prob. 15QCh. 17 - Prob. 16QCh. 17 - Prob. 17QCh. 17 - Prob. 18QCh. 17 - Prob. 19QCh. 17 - Prob. 20QCh. 17 - Prob. 21QCh. 17 - Prob. 22QCh. 17 - Prob. 23QCh. 17 - Prob. 24QCh. 17 - Prob. 25QCh. 17 - Prob. 26QCh. 17 - Prob. 27QCh. 17 - Prob. 28QCh. 17 - Prob. 29QCh. 17 - Prob. 30QCh. 17 - Prob. 31QCh. 17 - Prob. 32QCh. 17 - Prob. 33QCh. 17 - Prob. 34QCh. 17 - Prob. 35QCh. 17 - Prob. 36QCh. 17 - Prob. 37QCh. 17 - Prob. 38QCh. 17 - Prob. 39QCh. 17 - Prob. 40QCh. 17 - Prob. 41QCh. 17 - Prob. 42QCh. 17 - Prob. 43QCh. 17 - Prob. 44QCh. 17 - Prob. 45QCh. 17 - Prob. 46QCh. 17 - Prob. 47QCh. 17 - Prob. 48QCh. 17 - Prob. 49QCh. 17 - Prob. 50QCh. 17 - Prob. 51QCh. 17 - Prob. 52QCh. 17 - Prob. 53QCh. 17 - Prob. 54QCh. 17 - Prob. 55QCh. 17 - Prob. 56QCh. 17 - Prob. 57QCh. 17 - Prob. 58QCh. 17 - Prob. 59QCh. 17 - Prob. 60QCh. 17 - Prob. 61QCh. 17 - Prob. 62QCh. 17 - Prob. 63QCh. 17 - Prob. 64QCh. 17 - Prob. 65QCh. 17 - Prob. 66QCh. 17 - Prob. 67QCh. 17 - Prob. 68QCh. 17 - Prob. 69QCh. 17 - Prob. 70QCh. 17 - Prob. 71QCh. 17 - Prob. 72QCh. 17 - Prob. 73QCh. 17 - Prob. 74QCh. 17 - Prob. 75QCh. 17 - Prob. 76QCh. 17 - Prob. 77QCh. 17 - Prob. 78QCh. 17 - Prob. 79QCh. 17 - Prob. 80Q
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