Barnards Star
This very modest little star, located just six light-years away in the direction of the constellation Ophiuchus, is the closest star that can be studied from the Northern Hemisphere -- but only with the aid of telescopes, since it is much too dim to be seen with the unaided eye. It's a dim red dwarf star like Proxima Centauri (and most of the other stars on our list of neighbors) which first caught astronomers' attention in 1916. In that year, Edward Emerson Barnard of California's Lick Observatory found that this star's motion across the sky is the fastest known.

While the constellations appear fixed and unchanging over a human lifetime or two, the stars do slowly change their positions over the centuries as the Sun and the other stars move through space at various speeds and in different directions. For most stars, this change in position on the sky is very slow, indeed -- the constellations of 10,000 years ago were only slightly different from what they look like now. But stars that are quite nearby can change their positions relatively rapidly, just as an automobile on a street right next to you zips past you quickly, but cars on a distant highway seem to crawl along.

Barnard's Star moves across the sky at a rate of about half a degree (the size of the Moon's diameter) every 175 years. As it moves across the sky, it also is getting closer to us. Calculations indicate that it will pass by us at a distance of 3 3/4 light-years (closer than alpha Centauri) -- in about A.D. 11,800!

As the star moves, it doesn't seem to follow a perfectly straight line. Careful observations over several decades by Peter van de Kamp and his colleagues at Sproul Observatory in Pennsylvania indicate that it may be ``wobbling'' slightly around a straight-line path. It is possible that this wobble comes from the star's being tugged this way and that by the gravity of one or more large planets orbiting around it. (Currently, planets around other stars can't be seen through telescopes from Earth if those planets are like the ones in our solar system. Not producing light by themselves, they would be very dim and so close to their stars that their feeble, reflected light would be swamped in glare.) Astronomers have found very faint companion stars using the ``wobble'' method, but no planets have been confirmed as yet. The work is continuing at several observatories.

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