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 10Q
To determine
(a)
The radial velocity of star.
To determine
(b)
The direction of motion of star relative to Earth.
To determine
(c)
The actual wavelength of star.
To determine
(d)
The reason for the answer depends on the distance of star from the Sun.
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A star has a measured radial velocity of 100 km/s. If you measure the wavelength of a particular spectral line of Hydrogen as 486.42 nm, what was the laboratory wavelength (in nm) of the line? (Round your answer to at least one decimal place.)
Which spectral line does this likely correspond to?
Balmer-alpha (656.3 nm)
Balmer-beta (486.1 nm)
Balmer-gamma (434.0 nm)
Balmer-delta (410.2 nm)
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
Imagine that you are an astronomer studying a star 4 parsecs away (a parsec is
3.09x1016
m). You measure the flux coming from this star with your telescope, getting
a value of 2.3x10-12 W m-².
What is the luminosity of this star?
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
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