where "r" is the distance of the L1 point from the smaller object, "R" is the distance between the two main objects, and "M"1 and "M"2 are the masses of the large and small object, respectively. (The quantity in parentheses on the right is the distance of L1 from the center of mass.) Solving this for "r" involves solving a quintic function, but if the mass of the smaller object ("M"2) is much smaller than the mass of the larger object ("M"1) then and are at approximately equal distances "r" from the smaller object, equal to the radius of the Hill sphere, given by: