They’re a happy family after all. The three closest stars to the solar system all revolve around one another, astronomers say, resolving a century-long debate.
The nearest of the three, Proxima Centauri, is a red dwarf 4.24 light years from us. It made a splash in August when astronomers reported that it hosts an Earth-mass planet where temperatures might be right for liquid water.
Just beyond that, 4.37 light years away, shine two bright stars named Alpha Centauri A and B. They orbit each other every 80 years and glow yellow and orange respectively. To the naked eye, they blend together to appear as the third brightest star in the night sky.
In contrast, Proxima Centauri is too dim to see without a telescope, so it was only discovered in 1915.
Ever since, astronomers have thought Proxima Centauri might revolve around Alpha Centauri A and B – but couldn’t prove it.
If Proxima is bound to them, then it must move through space with nearly the same velocity. Otherwise, the little star would escape their gravitational grasp. Proxima and the Alpha Centauri pair are 13,000 times further apart than the sun is from the Earth.
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