Of 40,000 Class M Stars, 18 Might Come (Sort of) Close

"Solar System 'Nemesis': Nearby Stars Could Pose Threat"
Mike Wall, Space.com (February 16, 2011)

"Astronomical detectives have assembled a stellar lineup, identifying a handful of nearby stars that may come close enough to disturb our solar system in the next billion years or so.

"Researchers calculated the orbits of 40,000 low-mass M-dwarf stars and found 18 that may come dangerously close to our cosmic neighborhood in the next billion years. While the chances of this actually happening are probably slim, researchers said, the results could be dramatic.

" 'The probability of an M dwarf running into the sun is essentially zero,' said study lead author John Bochanski of Pennsylvania State University, who presented the results in Seattle last month at the 217th meeting of the American Astronomical Society. 'But if one just came close, it could still cause comet showers.'..."

"Close" is a comparative term, of course. That chart, showing how close a few nearby stars may come over the next billion or so years, is marked off in kpc, or kiloparsecs. One parsec, or parallax second, is about 3.26 light years, or - a whacking long distance compared to driving down to the grocery.

The astronomers are quite calm about what they've found, since they almost certainly know just how big - and small - the numbers are that they reported. What happens when some movie producer hears what someone said about the "Nemesis" stars - well, there was that '2012' stuff. (November 16, 2009)

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