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Big Dipper "Star" Actually a Sextuplet System

Posted by kdawson on from the toil-and-trouble dept.

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."

4 of 88 comments (clear)

  1. Only 78 light years away by JoshuaZ · · Score: 5, Interesting

    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.

    1. Re:Only 78 light years away by Anonymous Coward · · Score: 2, Interesting

      And being stars, even dim, they're easily some of the most visible objects in the sky. Consider just the Solar system and how many things in it that we don't know about. There's probably more we don't know about just within the heliopause than there is that we do know about.

    2. Re:Only 78 light years away by mcgrew · · Score: 4, Interesting

      The surprising thing is that this is only about 80 light years away. That's practically our next door neighbor.

      And if that star has a planet that had a species that had a SETI fifty years ago, they would have to keep searching for another twenty to forty years to pick up evidence of Earth having an intelligent species. They'd be waiting until 2119 before they heard the first human voice.

      I'm curious, does anyone know how many stars there are within a hundred light year radius of the sun? My googlefu is weak today...

      --
      Free Martian Whores!
  2. Nightfall by hazem · · Score: 4, Interesting

    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.