Due to their small separation , the two objects have never been visually resolved .
Due to their small separation , the two objects have never been visually are merely predicted from the radial velocity changes of GJ 3991 A , making the system a spectroscopic binary .
Due to their small separation , the two objects have never been visually resolved and are merely predicted from the radial velocity changes of GJ 3991 A , making the system a spectroscopic binary .