Astrophysicists find wide binary stars wreak havoc in planetary systems
Unlike the Sun, many stars are members of binary star systems – where two stars orbit one another – and these stars' planetary systems can be altered by the gravity of their companion stars. The orbits of very distant or wide stellar companions often become very eccentric – ie. less circular – over time, driving the once-distant star into a plunging orbit that passes very close to the planets once per orbital period. The gravity of this close-passing companion can then wreak havoc on planetary systems, triggering planetary scatterings and even ejections.