Wide binaries = havoc in planetary systems

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Astrophysicists find wide binary stars wreak havoc in planetary systems

An international team of astrophysicists has shown that planetary systems with very distant binary stars are particularly susceptible to violent disruptions, more so than if they had stellar companions with tighter orbits around them.

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.

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