Astronomy - Mass of a Star

1. Nov 30, 2009

Unto

1. The problem statement, all variables and given/known data
...Hence show that the mass of the star is M = $$4\pi$$$$p_{c}$$$$\left(R^{3}/3 )$$

2. Relevant equations
M(r) = $$4 \pi$$$$p_{c}$$$$\left(r^{3}/3 - r^{4}/4R)$$
This is the shell mass

3. The attempt at a solution
I already found the shell mass via intergration, and I know that I have to build up an 'infinite' number of shells to get the whole mass of the star. But do I use integration or something else? What do I do?

2. Dec 1, 2009

Unto

Hello? You don't really need to know about Astronomy to answer this question, I'm just really dumb and unsure whether to intergrate to find the mass throughout the star. Please help.

3. Dec 1, 2009

clamtrox

Is your star supposed to have an even mass distribution? Because your formula for the mass shell seems really weird. For a constant density it should be proportional to r^2.