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!

Homework Help: Mass of a star

  1. Oct 16, 2005 #1
    Suppose there is a planetary system in which a planet with an average distance of 6 AU from the star has an orbital period of 3 years. What is the mass of the star?

    The answer should be in SOLAR MASSES.

    I tried to use the formula: P^2 = (4pi^2*a^3)/G(m+M)
    but it didnt work:(

    any hint?
  2. jcsd
  3. Oct 16, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

    This is a simple variation problem and you should recognize that

    [tex]\frac {M P^2}{R^3}[/tex]

    is a constant so you can easily setup the appropriate proportion.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook