"Near" Cygnus

[mapguy]

Interesting article (http://www.washingtonpost.com/national/health-science/newest-alien-planet-is-just-the-right-temperature-for-life/2011/12/05/gIQAPk1vWO_story.html) about Kepler 22b, which has been discussed in this thread (http://www.bautforum.com/showthread.php/58157-Interesting-extrasolar-planet-discoveries/page38). 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.

[Swift]

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.

[Jeff Root]

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.



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.



So near Cygnus might be OK.
If you can't see it, it doesn't matter where it is. :p

-- Jeff, in Minneapolis

[Gillianren]

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.

[Centaur]

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.

[mapguy]

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"?

[Gillianren]

Exactly.