Chapter 33, Problem 3Q

To determine

Some properties of a red giant star and describe about it.

Answer to Problem 3Q

Solution:

A red giant star is a large bright star formed when the hydrogen in the cores of regular stars is used up. The nuclear reactions that take place in the core cannot continue and the core begins to contract due to its own gravity. This brings the hydrogen in the shell into a zone where the temperature and pressure is conducive for fusion reaction, resulting in expansion of this layer. Since the star expands to a much larger size, its energy gets spread over a much larger area, because of which the surface temperature is lower and the star’s visible light output has shifted towards red.

Its main properties are:

i)It is much larger in size compared to the regular star from which it is formed (up to about 200 times that of the Sun).

ii)Its surface temperature is relatively lower than that of the star from which it is formed, resulting in its red color.

iii)It has very high luminosity (up to nearly 3000 times that of the Sun).

Explanation of Solution

A red giant star is a cool star with reddish color. There is a fusion around the core shell. On fusing He and Be we get heavier nuclei.