How to Determine Energy Transfer Type in a Star from Density and Radius?

[atomqwerty]

Homework Statement

The statement is just this: For a given density p = p(r), being p==rho and r the radius of the star, how can I determinate whether the star has convective or radiative energy transfer?

Homework Equations

Equilibrium (1)
Continuity (2)
Ideal gas (3)
Schwarzschild criteria? (4)

The Attempt at a Solution

I calculate P(r) using (1) (and eventually (2) since p=p(r)). I write P=P(p) [remember p==rho] using (3). The problem is that I know two or three expressions for the temperature gradient, but they are valid only if the star is convective, radiative, etc. that is what I've been asked to decide.

Thanks

 

[zhermes]

All stars have some degree of convective and and radiative energy transfer. Often one of them is negligible. To find out, you need to know the total mass of the star, and generally its evolutionary state (i.e. age).

 

[atomqwerty]

All stars have some degree of convective and and radiative energy transfer. Often one of them is negligible. To find out, you need to know the total mass of the star, and generally its evolutionary state (i.e. age).

In most of the exercises that kind of data (numbers) are not provided. In one of them, it's given, for example, the density in terms of radius r, and with the only help of equations (1)-(3) I'm supossed to find out the temperature gradiente and, with it, the type of energy transfer in the star. Any clue? Thn