Spider binary systems contain a pulsar — the superdense, rapidly rotating remains of a star that exploded as a supernova — that slowly erodes its companion. An orbiting star begins to eclipse its partner, a rapidly rotating, superdense stellar remnant called a pulsar, in this illustration. Image credit: NASA / Sonoma State University / Aurore Simonnet. Spider systems develop because one star in a binary evolves more swiftly than its partner....
