Tossing comets at us Nemesis, as Muller sees it, is a common red dwarf star that would be visible through binoculars or a small telescope, if only we knew which of some 3,000 stars to look at. These are stars that have been cataloged, but their distances are not known. Any one of them could be the Death Star, as Nemesis has come to be called by some. Red dwarfs are the most common stars in the galaxy. They are small and relatively cool, dimmer than our Sun.
Binary stars settle into a gravitational dance around a common point in space.
The smaller of the two stars does most of the orbiting, whereas the larger one is much closer to the center of the dance routine. It's like two kids on a seesaw. For the thing to work properly, the heavier child must sit closer to the center of the apparatus. Muller figures Nemesis' orbit ranges from 1 to 3 light-years away from the Sun. On its closest approach, the lethal companion would pass through a vast, but sparsely populated halo of primitive comets called the Oort Cloud, which surrounds our solar system from beyond Neptune's orbit out to nearly a light-year away.