The binary star system Albireo.

Binary star systems make for unstable planets

A system’s galactic neighbors will throw orbits into chaos.

by Matthew Francis – Jan 7 2013, 2:30pm EST

In the last two years, astronomers discovered several exoplanets in binary systems: two stars locked in mutual orbit. These systems come in several types, with the planet orbiting one or both stars. About half the binary systems involve stars that are very far apart: 1000 times the Earth-Sun separation or more. Naively, we might think that those systems are more stable, since the companion star is so far away. However, a new study shows that may not be the case.

Nathan A. Kaib, Sean N. Raymond, and Martin Duncan ran extensive computer simulations to model exoplanets residing in wide binary systems. They found that perturbations from other stars outside the binary system had a profound effect on the shape of the system’s orbits. In some cases, planets were ejected from the system entirely or ended up in larger or highly eccentric (elongated) orbits. Based on these results, the researchers argued that some of the observed exoplanet systems with eccentric orbits may actually reside in wide binary systems where we haven’t yet detected the companion stars.

Read more: Binary star systems make for unstable planets | Ars Technica.

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