APOD: The Seagull Nebula (2012 Mar 08)

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Expand view Topic review: APOD: The Seagull Nebula (2012 Mar 08)

Re: APOD: The Seagull Nebula (2012 Mar 08)

by Chris Peterson » Fri Mar 09, 2012 2:42 pm

Ann wrote:An interesting thing about this nebula is the large detached round structure at upper left. This is the only part of the Seagull Nebula where the red emission nebulosity is tinted with the blue color of reflection nebulosity. In other words, here there be dust!
Probably no more dust than elsewhere- there's just a nicely placed star to scatter some light from it. The only reliable way to look at the dust content of the nebula would be an IR image.
My interpretation is that this "bright, but not so bright, blue, but not so blue" star is the star that ionizes the hydrogen around it and creates the large round red nebula. I think the dark winding filament is literally the star's "umbilical cord". I think the star was born out of this dust structure.
I think there's no relationship between the star and the dust column. Newly born stars can sit at the end of a tiny dust pillar, but they don't leave giant trails of dust like rocket launches, and long columns don't spout stars at their tips.

Re: APOD: The Seagull Nebula (2012 Mar 08)

by Ann » Fri Mar 09, 2012 6:28 am

An interesting thing about this nebula is the large detached round structure at upper left. This is the only part of the Seagull Nebula where the red emission nebulosity is tinted with the blue color of reflection nebulosity. In other words, here there be dust!

What about the bright but still not so bright blue but still not so blue star inside this round red but also a little blue nebula? And why does the star seem to be sitting at the end of a long and winding dark dust filament?

My interpretation is that this "bright, but not so bright, blue, but not so blue" star is the star that ionizes the hydrogen around it and creates the large round red nebula. I think the dark winding filament is literally the star's "umbilical cord". I think the star was born out of this dust structure. I think the reason why the star is "bright, but so so bright, and blue, but not so blue" is because it has been reddened by dust. According to my software, this star is of spectral class B0IV. I rather question the "IV", which suggests that the star is running out of hydrogen in its core, which in turn implicates that the star has been around a bit. In my opinon, however, the large amount of dust around the star suggests that the star must be quite young, otherwise it ought to have blown away more of the dust around it.

The color index of the star is about +0.35. That is very red for a star of spectral class B0, whose color index ought to be around -0.2. Its V magnitude is around +7, which, coupled with its parallax, suggests that this star is about as bright as 88 stars like the Sun. But that is much too faint for a young star of spectral class B0, which ought to be several hundred times as bright as the Sun. Again the explanation is dust reddening. The dust both dims and reddens the hot bright blue star, making it look redder and dimmer. On the other hand, some of the "lost" blue starlight is showing up as a blue reflection nebula.

I think it is fascinating, nevertheless, that we can see what is probably the "umbilical cord" of this star. The entire structure reminds me of the Cocoon Nebula.

Ann

Re: APOD: The Seagull Nebula (2012 Mar 08)

by saturn2 » Fri Mar 09, 2012 3:47 am

Happy day for women worldwide :D

Re: APOD: The Seagull Nebula (2012 Mar 08)

by neufer » Thu Mar 08, 2012 11:17 pm

Click to play embedded YouTube video.

Re: APOD: The Seagull Nebula (2012 Mar 08)

by neufer » Thu Mar 08, 2012 9:41 pm

http://www.csmonitor.com/Science/2012/0308/Tiny-dinosaur-sported-shimmery-black-coat-decorative-streamers-four-wings wrote:
Tiny dinosaur sported shimmery black coat, decorative streamers, four wings

The newly discovered fossil of Microraptor lived about 130 million years ago,
during the early Cretaceous period, in what is now northeastern China.
By Jennifer Welsh, LiveScience Staff Writer / March 8, 2012

<<A new fossil of a four-winged dinosaur about the size of a pigeon shows he apparently sported quite the costume, complete with glossy black feathers and a tail tipped with a pair of decorative streamer feathers.

The newly discovered fossil of Microraptor lived about 130 million years ago, during the early Cretaceous period, in what is now northeastern China. The latest depictions of the beast, whose feathery adornments may have extended to other Microraptor species, suggest it looked similar to a crow, even though non-avian dinosaurs had already separated from the ancestors of modern birds by that time.

It may have looked like a crow, but researchers also think it may have flashed its tail feathers in the manner of a peacock.

The researchers analyzed the fossil feathers using a scanning electron microscope to see melanosomes, tiny structures (about one-hundredth as wide as a human hair) that give feathers their colors. The researchers compared the arrangement of these melanosomes with those of modern birds. When melanosomes are stacked neatly, the feather looks darker; when they are more disorganized, the feather appears lighter.

From their analysis of modern birds, the researchers figured that this Microraptor fossil had black feathers. Furthermore, the narrow stacking of the melanosomes would have given the feathers iridescence. The researchers couldn't be sure of the color of the sheen, or the effect of the iridescence on the feather color, because those factors depend on the thickness of the feather's keratin coat.

"That keratin is not preserved in the fossil, so we couldn't directly infer a particular color of iridescence," said study researcher Matthew Shawkey, an assistant professor at the University of Akron, in Ohio.

Microraptor also had elongated tail feathers, which were much better preserved in this new specimen than in previous fossils. (The firstMicroraptor was unearthed in 2003.) The researchers could see these feathers were narrower and longer than previous extimates.

"People had interpreted [the tail feathers] as being helpful in aerodynamics, but now we know it wasn't aerodynamic, it actually probably hindered in flight," Shawkey said. Though the researchers think this Microraptor could fly, the long feathers were more likely there for decorative purposes.

The showy feathers, including the decorative ones on the tail, were likely used in courtship or other social interactions, like the tail of the peacock, the researchers say. "I think this is the first example of these very early ornamental tail feathers," Shawkey said. "Whether they lifted their tail up [like a peacock]… there's a possibility that they could have actively displayed it."

The study will be published in the March 9 issue of the journal Science.>>

Re: APOD: The Seagull Nebula (2012 Mar 08)

by orin stepanek » Thu Mar 08, 2012 9:27 pm

Sandstone wrote:Although I find today's image aesthetically more pleasing, this image:

http://apod.nasa.gov/apod/ap100319.html

Makes the moniker "seagull nebula" more obvious.
Nice; there I see a bird! 8-)

Re: APOD: The Seagull Nebula (2012 Mar 08)

by Sandstone » Thu Mar 08, 2012 8:24 pm

Although I find today's image aesthetically more pleasing, this image:

http://apod.nasa.gov/apod/ap100319.html

Makes the moniker "seagull nebula" more obvious.

Re: APOD: The Seagull Nebula (2012 Mar 08)

by orin stepanek » Thu Mar 08, 2012 1:52 pm

I do have trouble seeing a seagull! The very top looks like a dog's head to me! I guess i don't have the right perception of this nebula; but I do like it. :wink:

Re: APOD: The Seagull Nebula (2012 Mar 08)

by owlice » Thu Mar 08, 2012 9:48 am

ritwik wrote:

lazy robot need some fixing

tomorows pic is also posted before- northern trifid

http://apod.nasa.gov/apod/ap090130.html
Today's object has been shown before, but today's image is a new one. APODs are selected and the explanations written by real people (two astrophysicists, Robert Nemiroff and Jerry Bonnell); "APOD Robot" is a script written (by a real person, board admin geckzilla) to post each day's APOD image, text, and links here on the message board. No one's being lazy, and the robot does not need fixing. Well, not for having posted this image, anyway; every once in a great while, Otto Posterman does act up a bit.

Congratulations to Harel Boren! His image first appeared on the board on this thread.

APOD: The Seagull Nebula (2012 Mar 08)

by ritwik » Thu Mar 08, 2012 8:51 am


lazy robot need some fixing

tomorows pic is also posted before- northern trifid

http://apod.nasa.gov/apod/ap090130.html

Re: APOD: The Seagull Nebula (2012 Mar 08)

by Sandstone » Thu Mar 08, 2012 7:43 am

Re: APOD: The Seagull Nebula (2012 Mar 08)

by ritwik » Thu Mar 08, 2012 7:17 am

Re: APOD: The Seagull Nebula (2012 Mar 08)

by Beyond » Thu Mar 08, 2012 5:30 am

Decisions, decisions. Is it a Parrot nebula, or a Seagull nebula. The description says both. Maybe i'll just say that i sea a Parrotgull nebula and let it go at that. :yes: :mrgreen:

APOD: The Seagull Nebula (2012 Mar 08)

by APOD Robot » Thu Mar 08, 2012 5:05 am

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). IC 2177 forms the sweeping arc of the seagull's wings. 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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