Question

Suppose a star with the Sun’s mass and radius (the radius of the Sun is 6.96×10⁸ m) is rotating with a period of 25 days. The star first blows off its outer layers and loses mass and angular momentum before the actual collapse, thereby reducing its radius while maintaining the same density. Then, with a mass that is 59 % of the Sun’s mass, it collapses to a white dwarf with a rotation period is 131 s.

A) What is the radius of this white dwarf?

B) Compare your answer with the radius of Earth.

C) Compare your answer with the radius of the Sun.   

Answer 1

Here we apply concept of conservation of angular momentum.