(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Given the semimajor axis of Jupiter's orbit: 5.2 AU, and the eccentricity: .048 and the period: 11.86 years, find the total angular momentum of the Jupiter-Sun system. Assume it is an isolated system - ignore interactions from other planets etc.

2. Relevant equations

The first equation at the top of this page:http://en.wikipedia.org/wiki/Angular_momentum

plus various geometric equations concerning ellipses.

3. The attempt at a solution

I wish I had one. My thought process is that I should find the angular momentum of each mass about the location of the center of mass which could be calculated easy enough. Since angular momentum is conserved, I can pick any arbitrary location and then calculate it. The problem I'm running into is mainly - assuming the above approach is correct - how to find the velocity of either Jupiter or the Sun at a given point on its orbit. With enough time perhaps I could derive an equation using Newton's universal gravitation law and what not, but I've been staring at this problem for a while and nothing is coming to me. Maybe my approach is inherently flawed...any help is appreciated. Thanks.

edit: this is problem 2.6 in An Introduction to Modern Astrophysics, 2nd Ed.

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# Homework Help: Total Angular Momentum of A System

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