# Given that the Sun’s lifetime is about 10 billion years, estimate the life expectancy of a 0.2-solar mass white dwarf, a 3.0-solar mass star, and a 10-solar mass blue giant. The life expectancy of a particular star has inversely proportional relationship with its mass. Therefore if the mass of the star is less than solar mass, it will have a longer life than the sun and if the mass of the is greater than the solar mass, it will have...

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The life expectancy of a particular star has inversely proportional relationship with its mass. Therefore if the mass of the star is less than solar mass, it will have a longer life than the sun and if the mass of the is greater than the solar mass, it will have a shorter life than the sun.

The equation to calculate the life expectancy of the a star wrt the sun is give by (see source),

`t_s/t_0 = (M_s/M_0)^-2.5`

Where,

`t_s` = the life expectancy of the star

`t_0` = the life expectancy of the sun

`M_s` = the mass of the star

`M_0` = the mass of the sun

a) 0.2-solar mass white dwarf

`t_s/10 = (0.2)^-2.5`

`t_s = 559` billion years

b) 3.0 solar mass star

`t_s/10 = (3)^-2.5`

`t_s = 0.64` billion years

c) 10 solar mass blue giant.

`t_s/10 = (10)^-2.5`

`t_s = 0.03` billion years

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