Slashdot Mirror
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.
http://marsandmore.com - Posters of space, spacecraft, and astronomy.
It just goes to show you that there's always something more to learn.
The whole moon and the entire sky are reflected in one dewdrop on the grass. - Dogen
2*2 form Mizar, and 2 form Alcor; all six stars are gravitationally bound, and to the (untrained) naked eye look like a single star. So, the whole system is sextuplet.
"four-star Mizar system".
Nerd rage is the funniest rage.
in the year 2110, the mizar-alcor system will be discovered to actually be a septuple star system
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
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.
My big dipper is a sextuplet system too...
I suggested to my wife we try the sextruplet system with my big dipper and the neighbors, but she would have none of it.
By using extrapolation, I conclude that by 2020 we'll have discovered dozens of stars in the Mizar-Alcor system.
That group has also recorded a rough spectrum of the star, which Mamajek says confirms his prediction that the companion is a cool and dim M-class dwarf star.
...so it should at least have Roddenberries
Did you know that "FTW" ("for the win") is a direct translation of "Sieg Heil"?
AU means astronomical unit, not atomic unit. In your case, the measurement in Bohr radius doesn't qualify.
I read Slashdot for the headlines, because the headlines, unlike the articles, are usually original and never duplicated
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!"
2*2 form Mizar, and 2 form Alcor; all six stars are gravitationally bound, and to the (untrained) naked eye look like a single star.
Actually Mizar and Alcor are visibly distinct to somebody with a good eye.
1... 2... 3...
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.
So you are telling me that this system now has 6 suns instead of 4?
I think this calls for George Lucas to redo all the star wars movies YET AGAIN, with
a new backdrop featuring the 6 suns, as it could very well be a cooler movie with 6 instead of 2!!!
Obviously, this star system is the setting for Asimov's Nightfall.
(Technically not, as--if you read carefully--it is mentioned that Kalgash is near the galactic core... but it's an interesting thought regardless.)
>> Standing on head makes smile of frown, but rest of face also upside down.
So what you're saying is that it's stars all the way down?
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
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
How close do the stars have to be to be considered a binary (or n-ary) system? Isn't every star in the galaxy ultimately rotating around every other star in the galaxy?
I've abandoned my search for truth; now I'm just looking for some useful delusions.
I beg to differ with your question. Think of the solar system comprising the sun, planets of various sizes and compositions (including several "gas planets" that are, arguably, just slightly-too-small proto-stars, and right out to the "scattered disc" and even the Oort cloud. So, from Mercury outwards*, there are objects that orbit the sun. Distance, like size, does not matter: It's all orbital mechanics. (* And, yes, some objects notably comets 'orbit' - for some of their regular orbital period - well inside the orbit of Mercury then spend a great deal of the orbit a great distance further out in the solar system.)
Looking at space, radio, science and computing from a 'down-under' amateur enthusiast perspective.
I wonder how many geeks are going to get laid using that one this Christmas.
Nightfall from Azimov took place there.