Universe
11th Edition
ISBN: 9781319039448
Author: Robert Geller, Roger Freedman, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 19, Problem 30Q
To determine
The reason to attribute a Cepheid variable’s Doppler shift to its pulsation and not its orbital motion.
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(Astronomy)
(Part A) White Dwarf Size II. The white dwarf, Sirius B, contains 0.98 solar mass, and its density is about 2 × 106 g/cm3. Find the radius of the white dwarf in km to three significant digits. (Hint: Density = mass⁄volume, and the volume of a sphere is 4/3πr3).
(Part B) Compare your answer with the radii of the planets listed in the Table A-10. Which planet is this white dwarf is closely equal to in size?
A main sequence star of mass 25 M⊙has a luminosity of approximately 80,000 L⊙. a. At what rate DOES MASS VANISH as H is fused to He in the star’s core? Note: When we say “mass vanish '' what we really mean is “gets converted into energy and leaves the star as light”. Note: approximate answer: 3.55 E14 kg/s b. At what rate is H converted into He? To do this you need to take into account that for every kg of hydrogen burned, only 0.7% gets converted into energy while the rest turns into helium. Approximate answer = 5E16 kg/s c. Assuming that only the 10% of the star’s mass in the central regions will get hot enough for fusion, calculate the main sequence lifetime of the star. Put your answer in years, and compare it to the lifetime of the Sun. It should be much, much shorter. Approximate answer: 30 million years.
velocity curve for a double line
spectroscopic binary is shown in the sketch.
The system is viewed edge-on, i.e., with an
inclination angle of i = 90°, so that the
maximum possible Doppler shifts for this
system are observed.
400
300
So = U, Ani
200
t0 = v Ain i
100
-100
-200
-300
400
O 1 2 3 1 s 1 8: 10
Time (days)
Find the orbital period of this binary in days.
Doppler Velocity (krn/sec)
Chapter 19 Solutions
Universe
Ch. 19 - Prob. 1CCCh. 19 - Prob. 2CCCh. 19 - Prob. 3CCCh. 19 - Prob. 4CCCh. 19 - Prob. 5CCCh. 19 - Prob. 6CCCh. 19 - Prob. 7CCCh. 19 - Prob. 8CCCh. 19 - Prob. 9CCCh. 19 - Prob. 10CC
Ch. 19 - Prob. 11CCCh. 19 - Prob. 12CCCh. 19 - Prob. 13CCCh. 19 - Prob. 14CCCh. 19 - Prob. 15CCCh. 19 - Prob. 1QCh. 19 - Prob. 2QCh. 19 - Prob. 3QCh. 19 - Prob. 4QCh. 19 - Prob. 5QCh. 19 - Prob. 6QCh. 19 - Prob. 7QCh. 19 - Prob. 8QCh. 19 - Prob. 9QCh. 19 - Prob. 10QCh. 19 - Prob. 11QCh. 19 - Prob. 12QCh. 19 - Prob. 13QCh. 19 - Prob. 14QCh. 19 - Prob. 15QCh. 19 - Prob. 16QCh. 19 - Prob. 17QCh. 19 - Prob. 18QCh. 19 - Prob. 19QCh. 19 - Prob. 20QCh. 19 - Prob. 21QCh. 19 - Prob. 22QCh. 19 - Prob. 23QCh. 19 - Prob. 24QCh. 19 - Prob. 25QCh. 19 - Prob. 26QCh. 19 - Prob. 27QCh. 19 - Prob. 28QCh. 19 - Prob. 29QCh. 19 - Prob. 30QCh. 19 - Prob. 31QCh. 19 - Prob. 32QCh. 19 - Prob. 33QCh. 19 - Prob. 34QCh. 19 - Prob. 35QCh. 19 - Prob. 36QCh. 19 - Prob. 37QCh. 19 - Prob. 38QCh. 19 - Prob. 39QCh. 19 - Prob. 40QCh. 19 - Prob. 41QCh. 19 - Prob. 42QCh. 19 - Prob. 43QCh. 19 - Prob. 44QCh. 19 - Prob. 45QCh. 19 - Prob. 46QCh. 19 - Prob. 47QCh. 19 - Prob. 48QCh. 19 - Prob. 49QCh. 19 - Prob. 50QCh. 19 - Prob. 51QCh. 19 - Prob. 52QCh. 19 - Prob. 53QCh. 19 - Prob. 61Q
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