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How a planet could survive a collision between its two suns

first_imgWhile searching for Earth-like planets, NASA’s Kepler spacecraft has come across 10 that share one very un-Earth-like quality: They orbit two stars, instead of one. The worlds are aptly named “circumbinary planets” (“circum” meaning around, and “binary” referring to two objects), and in this type of binary system, the two stars orbit each other while the planet orbits the two stars (pictured above). But only the lucky binaries seem to have planets that orbit them; some stellar binaries that lack orbiting bodies have a different third party—a distant star that’s so massive, its gravitational fluxes actually change the orbit of the stellar binary, causing the two stars to shrink together in a process called orbital decay. If left uninterrupted, the stars will eventually collide together in a violent, calamitous explosion. Now, astronomers have asked a new question: What would happen if a circumbinary planet were in the mix? Naturally, one assumes its inevitable, fiery demise. But findings, published online 9 July in the Proceedings of the National Academy of Sciences, reveal that may not be the case. Using a combination of theoretical and numerical formulas, astronomers calculated that the planet may actually be able to survive the blast. The difference between life and death depends on that third, distant body. The researchers mathematically showed that the same mechanism that forces the binary together shifts the alignment of the circumbinary planet, potentially allowing it to sneak far enough away to escape incineration. Even so, surviving without a home base is a bit of a lonely swap.last_img read more

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