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Pulverized Planet Dust May Lie Around Double Stars

Tight double-star systems might not be the best places for life to spring up, according to a new study using data from NASA’s Spitzer Space Telescope. The infrared observatory spotted a surprisingly large amount of dust around three mature, close-orbiting star pairs. Where did the dust come from? Astronomers say it might be the aftermath of tremendous planetary collisions.

The particular class of double stars in the study, RS Canum Venaticorums (RS CVns for short), are separated by only about two million miles, or two percent of the distance between Earth and our sun. The stellar pairs orbit around each other every few days, with one face on each star perpetually locked and pointed toward the other.

The close-knit stars are similar to the sun in size and are probably about a billion to a few billion years old — roughly the age of our sun when life first evolved on Earth. But these stars spin much faster, and, as a result, have powerful magnetic fields, and giant, dark spots. The magnetic activity drives strong stellar winds that slow the stars down, pulling the twirling duos closer over time. And this is where the planetary chaos may begin.

As the stars cozy up to each other, their gravitational influences change, and this could cause disturbances to planetary bodies orbiting around both stars. Comets and any planets that may exist in the systems would start jostling about and banging into each other, sometimes in powerful collisions.

Above: (1) This artist’s concept illustrates an imminent planetary collision around a pair of double stars. (2) This artist’s concept illustrates a tight pair of stars and a surrounding disk of dust — most likely the shattered remains of planetary smashups.