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APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sat Jan 11, 2014 5:06 am
by APOD Robot
Image The Seagull Nebula

Explanation: A broad expanse of glowing gas and dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker - The Seagull Nebula. This portrait of the cosmic bird covers a 1.6 degree wide swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation Canis Major. Of course, the region includes objects with other catalog designations: notably NGC 2327, a compact, dusty emission region with an embedded massive star that forms the bird's head (aka the Parrot Nebula, above center). Dominated by the reddish glow of atomic hydrogen, the complex of gas and dust clouds with bright young stars spans over 100 light-years at an estimated 3,800 light-year distance.

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Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sat Jan 11, 2014 7:13 am
by Ann
This is a great image, and the Seagull Nebula is wonderfully photogenic and fascinating site of star formation. There are embedded stars, clusters and nebulosity all over the place!

A thing I really like about the Seagull Nebula and NGC 2327 is that it demonstrates so fantastically clearly that star formation may take place at the end of a long "tube" of dark nebulosity. Another example of the same phenomenon is the Cocoon Nebula, but the Seagull Nebula demonstrates this phenomenon even more dramatically. And the "wings" of the Seagull are slightly reminiscent of "the wall" in IC 1805 and Melotte 15. In both cases star formation is taking place on both sides of a "dividing line of nebulosity", although Melotte 15 produces a lot more ultraviolet light and a lot stronger stellar winds than the stars in and near the Seagull Nebula, so that the wall in Melotte 15 is a lot more contorted than "the ridge" in the wings of the Seagull.

Two clusters can be seen in today's APOD, NGC 2335 at about 8 o'clock, and NGC 2343 at 6 o'clock. NGC 2335 is clearly a somewhat oldish open cluster, because it is spread out, the colors of the stars are muted, and few stars stand out because of their brightness. NGC 2343, by contrast, is young. It is concentrated, many of the stars are blue, and the stars are relatively bright.

I can't resist showing you this image of the Seagull Nebula, where you can see that there is a red giant in NGC 2343. At bottom left in the same image you can see an even rarer bird than a seagull, an O-type star, HD 54662, the only O-type star in or near the Seagull Nebula.

Ann

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sat Jan 11, 2014 12:20 pm
by Beyond
Ah... Nebulosity... the characteristic of being nebulous; cloudiness (measured in octas)
The only thing Google could find about an octa, is that it is 1/8 the cloud cover of the sky.

octapus

Posted: Sat Jan 11, 2014 3:38 pm
by neufer
Ann wrote:
A thing I really like about the Seagull Nebula and NGC 2327 is that it demonstrates so fantastically clearly that star formation may take place at the end of a long "tube" of dark nebulosity.
Beyond wrote:
Ah... Nebulosity... the characteristic of being nebulous; cloudiness (measured in octas)
The only thing Google could find about an octa, is that it is 1/8 the cloud cover of the sky.
NEBULOSITY: the quality or state of being nebulous
. <the stupefying nebulosity of his philosophical musings>

Words that rhyme: atrocity, ferocity, monstrosity, velocity, viscosity, animosity, curiosity, generosity.

Synonyms: ambiguity, ambiguousness, darkness, equivocalness, equivocation, inscrutability, inscrutableness, murkiness, mysteriousness, obscurity, nebulousness, obliqueness, obliquity, opacity, opaqueness

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sat Jan 11, 2014 5:27 pm
by Coil_Smoke
This is the a most interesting image. I am intrigued by so many apparent strings, tri-nary , bi-nary and small clusters of stars. Many have one or more striking red and orange stars in them. Blowing this detailed image up reveals so many nebula, arcs , bow shocks and even a "Comet like" star in the extreme upper right. Good Fun :mrgreen: ...C-S

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sat Jan 11, 2014 6:46 pm
by Boomer12k
WOW...what a great shot!!!

But it looks more like a Parrot, to me...

Thanks.

:---[===] *

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sat Jan 11, 2014 9:44 pm
by starsurfer
Once again, the error of the large bright 'head' being identified as NGC 2327 is perpetuated. This part is catalogued as vdB93 and Sh2-292. NGC 2327 is a reflection nebula near the top right corner of the image. The coordinates for NGC 2327 in both the SIMBAD and NED databases refer to this reflection nebula and not the 'head'. A closeup of the "real" NGC 2327 by Adam Block: http://www.caelumobservatory.com/gallery/n2327.shtml
Also a paper about the NGC 2327 region: http://www.aanda.org/articles/aa/abs/20 ... h3484.html

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sun Jan 12, 2014 4:13 pm
by Ann
starsurfer wrote:Once again, the error of the large bright 'head' being identified as NGC 2327 is perpetuated. This part is catalogued as vdB93 and Sh2-292. NGC 2327 is a reflection nebula near the top right corner of the image. The coordinates for NGC 2327 in both the SIMBAD and NED databases refer to this reflection nebula and not the 'head'. A closeup of the "real" NGC 2327 by Adam Block: http://www.caelumobservatory.com/gallery/n2327.shtml
Also a paper about the NGC 2327 region: http://www.aanda.org/articles/aa/abs/20 ... h3484.html
Very interesting, starsurfer. My software agrees with you. However, I googled NGC 2327 and repeatedly got the "head" of the seagull, so I thought that my software might be in error. According to you, it is not.

Ann

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Sun Jan 12, 2014 4:22 pm
by geckzilla
NGC 2327 seems to be in the wing tip.

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Tue Jan 14, 2014 6:44 pm
by starsurfer
Ann wrote:
starsurfer wrote:Once again, the error of the large bright 'head' being identified as NGC 2327 is perpetuated. This part is catalogued as vdB93 and Sh2-292. NGC 2327 is a reflection nebula near the top right corner of the image. The coordinates for NGC 2327 in both the SIMBAD and NED databases refer to this reflection nebula and not the 'head'. A closeup of the "real" NGC 2327 by Adam Block: http://www.caelumobservatory.com/gallery/n2327.shtml
Also a paper about the NGC 2327 region: http://www.aanda.org/articles/aa/abs/20 ... h3484.html
Very interesting, starsurfer. My software agrees with you. However, I googled NGC 2327 and repeatedly got the "head" of the seagull, so I thought that my software might be in error. According to you, it is not.

Ann
This is an error repeated by lots of people and when something is repeated in many sources, then people seem to accept it as fact. Another one is NGC 6820 in Vulpecula, this designation is commonly used for the emission nebula when in fact it refers to a completely different object and the emission nebula is actually Sh2-86.

Re: APOD: The Seagull Nebula (2014 Jan 11)

Posted: Tue Jan 14, 2014 6:45 pm
by starsurfer
geckzilla wrote:NGC 2327 seems to be in the wing tip.
I don't know why nearly all images of the Seagull Nebula on APOD have an almost identical field of view. They don't include the whole Seagull Nebula, nobody ever thinks of poor little Ced 90 to the south. :(

Cederblad 90 / Gum 3

Posted: Tue Jan 14, 2014 7:03 pm
by neufer
starsurfer wrote:
geckzilla wrote:
NGC 2327 seems to be in the wing tip.
I don't know why nearly all images of the Seagull Nebula on APOD have an almost identical field of view. They don't include the whole Seagull Nebula, nobody ever thinks of poor little Ced 90 to the south. :(