1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Astrophysics - Energy radiated from a star through contraction

  1. May 1, 2010 #1

    1. The problem statement, all variables and given/known data
    As the sun evolved to the main sequence it contracted under gravity and its internal temperature changed from 3E4 K to 6E6 K. Assuming the sun is fully ionised at these temperatures estimate the energy radiated during this phase, stating your assumptions.

    2. Relevant equations
    I think this involves using the equation for gravitational potential energy and possible the scaling relation; Temp proportional to Mass/Radius for stars.

    3. The attempt at a solution
    I am not sure how to attempt this, my thinking is the temperature increase corresponds to a pressure decrease over which the radius of the sun decreases, thus releasing gravitational potential energy. But how would i relate the temperature change to a radius change?

  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted