Are you talking about stars in the astronomic sense? If so, they do occur in "binaries". Some famous stars are actually binaries, where the stars revolve around (usually) a common centre. If they stop revolving, typically, gravitational force will bring them together, sometimes with catastrophic consequences. Mizar, one of the stars in the "Big Dipper" is a binary. See "Main Sequence" and "Binary star" on Wikipedia for more (and more learned) information.