Concept explainers
Thetime period for which the Sun will be a red giant.
Answer to Problem 50Q
The Sun will be a red giant for
Explanation of Solution
Given:
The luminosity of the Sun if it becomes a red giant is,
Formula Used:
The luminosity of the star is given by,
Here,
Energy is emitted by the star by converting a fraction of total mass of the star and is given by,
Here,
Thus, the luminosity of the star is given by,
The ratio of the luminosity of a star for two different cases is given by,
Calculations:
Consider figure 19-9 of the book “Universe: Stars and Galaxies”; the main sequence lifetime of the Sun is
The Sun consumes hydrogen at the rate of
Therefore, the mass of hydrogen consumed by the Sun in
Solve further,
The standard value of the mass of the Sun is,
Assume the amount of hydrogen in the Sun at present is
The Sun is considered to be
Solve further,
The initial amount of hydrogen present in the Sun is calculated as,
The mass of hydrogen left after the main sequence lifetime of the Sun is calculated as,
The time period for which the Sun will be a red giant is calculated as,
Conclusion:
Thus, for
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Chapter 19 Solutions
Universe: Stars And Galaxies
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