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Name: Unknown
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Date: Prior to 1993

What is the closest star to the sun. Some sources say Alpha Centauri and others say Proxima Centauri is the closest. Both are reliable, but I am confused about which is the closest star?

The name "Alpha Centauri" actually denotes a triple star system in the constellation Centaurus (it appears as a single star to the naked eye). Two of these stars, denoted Alpha Centauri A and B, are very similar to the sun and are approximately 4.336 light-years away. They orbit each other (better said, they orbit their common center of mass) with a period of about 80 years. Then, orbiting this pair is a small, faint star only a tenth the size of the sun. This star takes one-and-a-half million years to orbit the larger pair; at the moment it is closer to us than the other two, a mere 4.205 light-years away. Because it is the nearest star to the sun, it is named Proxima (from the Latin word for "nearest") Centauri. This information came from "Astronomy: The Cosmic Journey", an astronomy text by William Hartmann. I did not know this stuff myself until now!

RC Winther

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