What are 7 elements from the periodic table that are named after objects in outer space

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

the answer is to check all of them! they all apply well at least i think so!