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Big Dipper "Star" Actually a Sextuplet System
Theosis sends word that an astronomer at the University of Rochester and his colleagues have made the surprise discovery that Alcor, one of the brightest stars in the Big Dipper, is actually two stars; and it is apparently gravitationally bound to the four-star Mizar system, making the whole group a sextuplet. This would make the Mizar-Alcor sextuplet the second-nearest such system known. The discovery is especially surprising because Alcor is one of the most studied stars in the sky. The Mizar-Alcor system has been involved in many "firsts" in the history of astronomy: "Benedetto Castelli, Galileo's protege and collaborator, first observed with a telescope that Mizar was not a single star in 1617, and Galileo observed it a week after hearing about this from Castelli, and noted it in his notebooks... Those two stars, called Mizar A and Mizar B, together with Alcor, in 1857 became the first binary stars ever photographed through a telescope. In 1890, Mizar A was discovered to itself be a binary, being the first binary to be discovered using spectroscopy. In 1908, spectroscopy revealed that Mizar B was also a pair of stars, making the group the first-known quintuple star system."
The surprising thing is that this is only about 80 light years away. That's practically our next door neighbor. The fact that there would be undiscovered stars that close is nothing short of amazing. The new star is very small and dim which helps explain why it was not previously discovered. Still this is a good example of how much we have left to learn. We don't even have a good understanding of our nearby stellar neighbors.
Alcor, the star in question, is the middle star on the "handle" of the dipper.
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It just goes to show you that there's always something more to learn.
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You don't even need to RTFA - it is in the summary. Miza is a binary of binaries and Alcor is a binary. (2+2)+2=6. So you would not guess correctly.
I suggested to my wife we try the sextruplet system with my big dipper and the neighbors, but she would have none of it.
More likely they'll be discovered to be giant glowing tribbles. How else do you explain it going from one star to six in just a few hundred years? ;)
~REZ~ #43301. Who'd fake being me anyway?
By using extrapolation, I conclude that by 2020 we'll have discovered dozens of stars in the Mizar-Alcor system.
FTFA: "In ancient times, people with exceptional vision discovered that one of the brightest stars in the Big Dipper was, in fact, two stars so close together that most people cannot distinguish them."
In ancient times the atmosphere was cleaner than now, and had a lot less light pollution from towns. Yet it apparently took "exceptional vision" to see Alcor and Mizar as separate stars. I must have phenomenal eyesight then to be able see them any night it isn't cloudy.
"Wait. Something's happening. It's opening up! My God, it's full of apricots!"
In case anyone was wondering (and since TFA doesn't mention it), the nearest sextuplet star, is, of course, Alpha Geminorum, a.k.a. Castor, the second-brightest star in the zodiac sign of Gemini, a.k.a. the Twins. It's some 50-odd lightyears away.
Note that Beta Geminorum, a.k.a. Pollux, is actually the brightest star in Gemini (whether Johann Bayer labelled Castor as the alpha star because it rises first in the night's sky, or because mythologically, the twins are always labelled "Castor and Pollux", is unknown). Pollux is a single star, with one confirmed exoplanet, Polydeuces orbitting it.
Indeed. And what an odd way to draw a chart, omitting a key to what counts as "80 light years". Does it count stars 80.1 light years away? 80.5? 82? Probably (79.5,80.5], but I've never seen "at" have an uncertainty of three trillion miles.
The source for that chart says there are 2539 stars within 80 light years (24.53 parsecs).
I couldn't help but think of Asimov's story, Nightfall. In it, a planet is in a 6-star system and is never dark. Interesting things happen.
Alcor is not one of the brightest stars in the Big Dipper. It is a dim double with Mizar. We usually consider the dipper to have 7 stars: 4 in the 'pot' and three in the handle. Mizar is the center of the handle. Alcor is so close to Mizar and relatively dim that it's not even considered a point in the constellation.
Not incorrect but misleading, Castelli was the first to see it as a double 'with a telescope'. The names themselves being Arabic, should be a tip off. Would Alcor have an Arabic name if they didn't see it? They are a visual double, not requiring a telescope to see if one has good vision (as opposed to an optical double, being line of sight but not necessarily naked eye). Such as noted by the Arabic chroniclers of astronomy, as well as the Native Americans who saw the bowl of the dipper as the bear, and the three stars in the handle as three bear cubs or some as three hunters (or sever, per the Mikmac) following the bear. All knew of the two stars. Sir Patrick Moore suggests the early writings refer to Mizar A and B instead, and gives good logical thinking, though I know of pre-tlescope maps of Mizar and Alcor, but not Mizar A and B,
"I may be synthetic, but I'm not stupid." -- Bishop 341-B