# Desperate for astrophysics help

1. Nov 27, 2005

### jaidon

The energy generation rate for p-p fusion has an approximate dependence on density and temperature given by:
E= e (p/pc)(T/Tc)^4

i don't know how to write all the symbols so in the above:

E is epsilon, e is epsilon at the centre of the star, p is the density, pc is density at the centre, Tc is temp at centre.

a) find the equation for the temperature within a constant density, ideal gas star to show how E depends on the radial distance from the centre of the star. Express your answer in terms of the fraction r/R where R is the total radius of the star and r is the distance from the centre.

I am lost. We have an equation for the pressure of a constant density star P(r)= (3GM^2/(8piR^4))(1-r^2/R^2). Ideal gas law tells us P= nkt where n= density/m. The average density of a star is 3M/4piR^3.

I can't figure this out. Any help, this assignment is due tomorrow.

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