Concept explainers
The reason behind a red dwarf not leaving the main sequence.

Answer to Problem 1CC
Solution:
To leave the main sequence, a red dwarf should finish converting its core hydrogen to helium, which also determines its lifetime, but it takes millions of years, which is more than the life of the universe.
Explanation of Solution
Introduction:
A red dwarf star belongs to the main sequence stars of M type. It is a small and cool star, its red color is due to cool temperature. A red dwarf has
Explanation:
Due to the thermonuclear reactions occurring in the core, helium is produced and this gets replaced by the hydrogen from the outer layers of the star. Convection cells of the rising and falling gases lead to the replacement of the helium produced in the core. This ultimately fuels the star and increases its lifetime. According to the calculations, this lifetime can be hundreds of billions of years, but the present age of the universe is 13.6 billion years only. Hence, a red dwarf cannot leave the main sequence.
Conclusion:
Due to its huge lifetime, a red dwarf is unable to leave the main sequence.
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Chapter 19 Solutions
EBK LOOSE-LEAF VERSION OF UNIVERSE
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