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Thread: "Near" Cygnus

  1. #1

    "Near" Cygnus

    Interesting article about Kepler 22b, which has been discussed in this thread. But I took issue with this sentence:

    "The planet’s home star, some 600 light years distant and near the constellation Cygnus, is “almost a solar twin,” Batahla said."

    So, what does that mean, that it's "near" Cygnus? Seems to me, it's either in Cygnus, or it's in another constellation.

  2. #2
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    I don't think every star is in a constellation. And I don't even know that the home star of Kepler 22b is even naked eye visible. So near Cygnus might be OK.
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  3. #3
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    Quote Originally Posted by Swift View Post
    I don't think every star is in a constellation.
    What? **WHAT???**

    Every star is in a constellation, though a few might wander
    back and forth across a boundary line every six months as
    Earth goes around the Sun. At a distance of 600 light-years,
    that isn't likely, but it isn't impossible.

    There are 88 constellations, and they cover the whole sky.
    Some are less familiar than others, and some writer might
    substitute a familiar nearby constellation for the actual
    unfamiliar one.

    However Wikipedia says Kepler-22 is "located between the
    constellations Cygnus and Lyra at Right Ascension 19h 16m
    52.2sec and Declination +47deg 53min 4.2sec." Both familiar
    constellations. That location is closer to Vega than to Deneb.
    The data table on the right side of the Wikipedia page lists
    the constellation as Cygnus. So it would seem that it is in
    Cygnus, but closer to the very bright star Vega, in Lyra, than
    to the bright star Deneb in Cygnus.

    Quote Originally Posted by Swift View Post
    And I don't even know that the home star of Kepler 22b is
    even naked eye visible.
    The Wiki page says it is apparent magnitude 11.664. Way
    far away from naked eye visible.

    Quote Originally Posted by Swift View Post
    So near Cygnus might be OK.
    If you can't see it, it doesn't matter where it is.

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  4. #4
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    Whether or not every star is in a constellation depends on your definition, actually. By some, "constellation" is a region of sky. By others, it's the actual stars which make up the image in question.
    _____________________________________________
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  5. #5
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    Smile

    Indeed, the term constellation literally means a group of stars. That’s what it meant until 1922 when the International Astronomical Union divided the celestial sphere into 88 (actually 89 if we count split Serpens) regions and called them constellations. It’s because of that that some insist there are thirteen zodiacal constellations instead of twelve. The IAU took a dim region of stars away from Scorpius and placed them in Ophiuchus. They also ask us to refer to groupings of stars other than their own as asterisms. e.g. The Big Dipper or Summer Triangle. I prefer the traditional definition of constellation (forget asterism), but will bow to the IAU when they assign a star to one of their defined constellations.
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  6. #6
    Quote Originally Posted by Gillianren View Post
    Whether or not every star is in a constellation depends on your definition, actually. By some, "constellation" is a region of sky. By others, it's the actual stars which make up the image in question.
    So, by the second definition, the only objects that would be described as "in Cygnus" would be the ten (or so) stars visible to the unaided eye which, when mentally connected, form a pattern resembling a swan? Everything else in the vicinity (telescopic or not) would be termed "near Cygnus"?

  7. #7
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    Exactly.
    _____________________________________________
    Gillian

    "Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

    "You can't erase icing."

    "I can't believe it doesn't work! I found it on the internet, man!"

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