1. The problem statement, all variables and given/known data In recent years, a number of nearby stars have been found to possess planets. Suppose, the orbital radius of such a planet is found to be 4.3 times 1011 m, with a period of 1080 days. Find the mass of the star. 2. Relevant equations ????? 3. The attempt at a solution I don't even know where to start with this question. Without the mass of the planet I am clueless. ANy help would be much appreciated, Thanks a lot.