# Astrophysics question

1. Feb 25, 2014

### MartenAndre

1. A star in the main series. Explain how the radiated power, surface temperature, lifetime and location in the HR diagram depends on the star's mass.

2.E = 1/4Pi*r^2 (I think, need help with this)

3.I know that the lifetime of the star depends on its mass because of the fusion process, or how fast the atoms in the star fuses (which is connected to the stars temperature). I know that radiation power is L which is how much energi per time it releases. This is found by using

Last edited by a moderator: Feb 25, 2014
2. Feb 25, 2014

### BvU

Under 2, I don't see a temperature, radiated power (or is that E? If so, mention it!) lifetime, etc.

3. Feb 25, 2014

### MartenAndre

What do you mean? An equation for the temperature, or radiated power?

4. Feb 25, 2014

### BvU

So the exercise is asking for a bunch of stuff, right? My naive idea would be that you need expressions for these things. If you want to do only one, fine with me!
Right now I see an expression for something called E with the dimension of m-2. What is it ?