1. Apr 26, 2010

### Max.Planck

Hello,

I have a question from the Dutch Astrophysics Olympiad, which I can't solve.

" Is there mathematical proof that stars are still being formed? "

In previous questions, i had to derive the following equations, which i need to use in my answer for the question above:

L = σ * T4 * 4πR2

(Luminosity-Temperature relation of a star, where σ is the Boltzmann constant, T is temperature and R is the radius of the star)

t = life time of sun * (M/Msun)-2,6

(where t equals the life time of a type V star and M equals mass)

Can anyone help me with this?

Thanks,

Max.Planck

2. Apr 26, 2010

### Matterwave

Re: New_Stars_being_formed

Observational evidence? yes. Mathematical proof? don't think so...

I don't see how you can get a mathematical proof for star formation...

Perhaps they are asking you to show that the life-time of some stars is less than that of the age of the universe and therefore if there was no star formation after the BB, we wouldn't see any of those stars...? This still relies on observation (of the massive stars), and it doesn't preclude the possibility that star formation has stopped this instant (rather than billions of years in the past).

I honestly can't think of any proof that would both not rely on observational evidence, and preclude the possibility of star formation stopping this instant.

Maybe I'm missing something here haha...

3. Apr 26, 2010

### silentbob14

Re: New_Stars_being_formed

Yeah it's a very interesting question ;] And a hard one indeed. It will be interesting to find out the answer.

4. May 2, 2010

### amarante

Re: New_Stars_being_formed

Luminosity is the amount of energy released by time...
and that life time you found I suppose is the time that the star spend in the Main Sequence, right? so actually if you find some stars, that you measure its luminosity and with this you would calculate that it would actually spend some Myears in the MS, so it means that they are younger than the Sun and actually stars are being created. So maybe, yes you can proove it mathematically, but I dont have here a paper and a pencil to write down things, but I think it is possible, with this 2 relations