Stars with the mass of the sun or larger are typically accompanied by one or more orbiting companion stars. The system forms when gravity contracts the gas and dust of an interstellar cloud until clumps develop that are dense enough to coalesce into stars. Multiple stellar systems develop, according to one model, when the cloud has a slight spin. That generates a disk that then fragments to produce multiple stars.
Click here for original story, Triply eclipsing stellar systems
Source: Phys.org