EBK FOUNDATIONS OF ASTRONOMY
14th Edition
ISBN: 8220106820612
Author: Backman
Publisher: YUZU
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Chapter 16, Problem 5P
To determine
The orbital period of the outer stars.
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Suppose that the outer stars of a galaxy have an orbital velocity of 150 km/s. If the radius of the galaxy is 4.0 kpc (1??? = 3.1 × 1016 ??), what is the orbital period of the outer
stars in years?
given:
a (distance to center of galaxy in AU) = 1,717,914,439 AU
P (suns orbital period in years) = 203,782,828.3 years
M (mass of milky way galaxy in solar masses) = 1.22 x 10^11 Msun
Question:
Assume the Milky Way Galaxy is made up entirely of stars like the Sun, i.e. on average each star has the mass of 1 MSun. Under this assumption, approximately how many stars are there in our galaxy? Express this answer in billions of stars (1 billion = 109).
The Tully-Fischer method relies on being able to relate the mass of a galaxy to its rotation velocity. Stars in the outer-most regions of the Milky Way galaxy, located at a distance of 50 kpc from the galactic centre, are observed to orbit at a speed vrot = 250 km s−1. Using Kepler’s 3rd Law, determine the mass in the Milky Way that lies interior to 50 kpc. Express your answer in units of the Solar mass.
Chapter 16 Solutions
EBK FOUNDATIONS OF ASTRONOMY
Ch. 16 - Prob. 1RQCh. 16 - Prob. 2RQCh. 16 - Prob. 3RQCh. 16 - Prob. 4RQCh. 16 - Prob. 5RQCh. 16 - Prob. 6RQCh. 16 - Prob. 7RQCh. 16 - Prob. 8RQCh. 16 - Prob. 9RQCh. 16 - Prob. 10RQ
Ch. 16 - Prob. 11RQCh. 16 - Prob. 12RQCh. 16 - How would you respond to someone who said, Oh,...Ch. 16 - Prob. 1PCh. 16 - Prob. 2PCh. 16 - Prob. 3PCh. 16 - Prob. 4PCh. 16 - Prob. 5PCh. 16 - Prob. 6PCh. 16 - Prob. 7PCh. 16 - Prob. 8PCh. 16 - Prob. 9PCh. 16 - Prob. 10PCh. 16 - Arrange the following in order of increasing size:...Ch. 16 - If the diameter of the Milky Way Galaxys visible...Ch. 16 - Prob. 1LTLCh. 16 - Prob. 2LTLCh. 16 - Prob. 3LTLCh. 16 - Prob. 4LTL
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