APOD: The Fairy of Eagle Nebula (2011 Aug 21)

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APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby APOD Robot » Sun Aug 21, 2011 4:08 am

Image The Fairy of Eagle Nebula

Explanation: The dust sculptures of the Eagle Nebula are evaporating. As powerful starlight whittles away these cool cosmic mountains, the statuesque pillars that remain might be imagined as mythical beasts. Pictured above is one of several striking dust pillars of the Eagle Nebula that might be described as a gigantic alien fairy. This fairy, however, is ten light years tall and spews radiation much hotter than common fire. The greater Eagle Nebula, M16, is actually a giant evaporating shell of gas and dust inside of which is a growing cavity filled with a spectacular stellar nursery currently forming an open cluster of stars. The above image in scientifically re-assigned colors was released in 2005 as part of the fifteenth anniversary celebration of the launch of the Hubble Space Telescope.

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Beyond » Sun Aug 21, 2011 4:28 am

A cloud of dust and a hearty Hi-Yo Eagle Nebula. Star-maker extraordinarie.
To find the Truth, you must go Beyond.

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby orin stepanek » Sun Aug 21, 2011 12:44 pm

Orin

Smile today; tomorrow's another day!

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Jim28625 » Sun Aug 21, 2011 12:47 pm

Has anyone ever postulated on the size of the star that went supernova to create this amazing structure? It had to have been the largest star in our galaxy at the time. I wonder how long ago it exploded? I bet a simulated time lapsed sequence of it forming from the supernova to now would be an amazing treat. Absolutely incredible!

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Chris Peterson » Sun Aug 21, 2011 4:20 pm

Jim28625 wrote:Has anyone ever postulated on the size of the star that went supernova to create this amazing structure? It had to have been the largest star in our galaxy at the time. I wonder how long ago it exploded? I bet a simulated time lapsed sequence of it forming from the supernova to now would be an amazing treat. Absolutely incredible!

This dust and gas didn't come from a supernova. It came from the ejected material of many supernovas, as well as from the smaller events that create planetary nebulas. Over time, gravity brings together dust and gas from different places, and new star forming regions form.
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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Ann » Sun Aug 21, 2011 4:26 pm

Well, this structure has some similarity to the Cocoon Nebula, which was the APOD a few days ago. Both the Fairy and the Cocoon have long "stems" ending in a cascade of star formation.

Although, of course, the Fairy nebula is a pre-existing dust cloud has been sculpted by strong stellar winds blowing "straight into the face" or at least "into the neck" of the Fairy, whereas the Cocoon is not pelted by "in-your-face" winds in the same way.

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby rascar » Sun Aug 21, 2011 5:08 pm

What is meant by "re-assigned colors?
What is the process involved? :?:

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby NoelC » Sun Aug 21, 2011 6:11 pm

rascar wrote:What is meant by "re-assigned colors?
What is the process involved? :?:

Though I did not uncover the specifics, I did find that this image was photographed through the following Hubble ACS camera filters, and the names encode the wavelength and the bandwidth of the filter:

F435W (B) - Wideband visual blue/indigo
F502N ([O III]) - Narrowband visual green/teal (optimized to measure ionized oxygen emissions)
F555W (V) - Wideband visualyellow-green
F658N (Halpha + [N II]) - Narrowband visual deep red (optimized to meaure ionized hydrogen emissions)
F814W (I) - Wideband near infrared

Notably, since one of the colors is not actually visible to the naked eye, some mapping of this color spectrum to the one we CAN see and represent in images had to be done. The image assembly from individual datasets was likely done in Photoshop, and the captured color spectrum was probably compressed so that near infrared data contributed a deep red color to the image, the red data contributed a more orange color, etc. I'll add that without having done the processing or having read an account of it it's impossible to say for sure how it was processed.

There is good information at the page the "released" link in the caption leads you to.

-Noel
Last edited by NoelC on Sun Aug 21, 2011 6:40 pm, edited 1 time in total.

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby NoelC » Sun Aug 21, 2011 6:38 pm

I suspect perhaps a bit of artistic license was employed as well, to help better visualize the different components of the nebula.

I combined the components provided by the Hubble Heritage team on the web page mentioned above, using the color mapping I described, and came up with this:

HubbleImage1.jpg


With just a bit of tweaking for best artistic presentation:

HubbleImage2.jpg


-Noel
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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Ann » Mon Aug 22, 2011 11:01 am

Very interesting, Noel. Thanks.

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby flash » Mon Aug 22, 2011 6:18 pm

APOD Robot wrote:
The dust sculptures of the Eagle Nebula are evaporating.
...
The greater Eagle Nebula, M16, is actually a giant evaporating shell of gas and dust


What sense of the word "Evaporate" is meant here? In common use, evaporate is of course meant as transition of matter from liquid to gas. (Sublimation for transition from solid directly to gas.) I presume that the matter in the nebula that is "evaporating" is already more tenuous than what we commonly experience as the results of evaporation here on Earth. So if the nebula already consists of "gas and dust", to what does it evaporate?

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Chris Peterson » Mon Aug 22, 2011 6:40 pm

flash wrote:What sense of the word "Evaporate" is meant here? In common use, evaporate is of course meant as transition of matter from liquid to gas. (Sublimation for transition from solid directly to gas.) I presume that the matter in the nebula that is "evaporating" is already more tenuous than what we commonly experience as the results of evaporation here on Earth. So if the nebula already consists of "gas and dust", to what does it evaporate?

It is simply becoming even more tenuous. In this context, it means "dissipate".
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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby flash » Tue Aug 23, 2011 12:18 pm

Chris Peterson wrote:It is simply becoming even more tenuous. In this context, it means "dissipate".

What I see in such images is a distinct boundary between the nebula's pillar "as in Pillars of Creation http://apod.nasa.gov/apod/ap100328.html" and the surrounding relatively empty space. I assume that the boundary is distinct due to the sharp change either in the density of the matter across the boundary or in the reflectivity (or luminosity) of that matter. Radiation (or solar wind) pushing the matter away (dissipating it) doesn't seem (to me, at least) a sufficient explanation for the distinct boundaries evident. In my experience, merely pushing dust around doesn't eliminate the dustiness: It merely moves the dust to somewhere else. Is there something else going on here?

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby Chris Peterson » Tue Aug 23, 2011 1:13 pm

flash wrote:
Chris Peterson wrote:It is simply becoming even more tenuous. In this context, it means "dissipate".

What I see in such images is a distinct boundary between the nebula's pillar "as in Pillars of Creation http://apod.nasa.gov/apod/ap100328.html" and the surrounding relatively empty space. I assume that the boundary is distinct due to the sharp change either in the density of the matter across the boundary or in the reflectivity (or luminosity) of that matter. Radiation (or solar wind) pushing the matter away (dissipating it) doesn't seem (to me, at least) a sufficient explanation for the distinct boundaries evident. In my experience, merely pushing dust around doesn't eliminate the dustiness: It merely moves the dust to somewhere else. Is there something else going on here?

I think we are seeing shock structures as well. So the dynamic of the nebula is defined by the inward force of gravity (which isn't a smooth field, but is "lumpy" because of the density gradients and concentrations), the outward (with respect to each member star) force of radiation pressure and solar wind, and the outward force of natural dissipation. The resulting movement creates shock fronts, and produces metastable structure.
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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby NoelC » Wed Aug 24, 2011 12:41 am

flash wrote:In my experience, merely pushing dust around doesn't eliminate the dustiness: It merely moves the dust to somewhere else. Is there something else going on here?

I question whether you've ever pushed enough dust around that the large mass of it created mutual gravitational attraction. I don't think the stuff you observe in the air in your room can be extrapolated to this scale.

Clearly it occasionally squeezes itself together well enough to make stars and planets. Why is it hard to imagine that this is a phase of that?

-Noel

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby flash » Wed Aug 24, 2011 12:33 pm

NoelC wrote:I question whether you've ever pushed enough dust around that the large mass of it created mutual gravitational attraction. I don't think the stuff you observe in the air in your room can be extrapolated to this scale.

Clearly it occasionally squeezes itself together well enough to make stars and planets. Why is it hard to imagine that this is a phase of that?


I have no trouble believing that vast expanses of tenuous dust and gas can mutually gravitate into denser clouds and then into stars and planets. My question was about the nature of the so-called "evaporation" (caused by radiation and solar wind) that is supposedly eroding such dense knots of dust and gas and making them less so. If these dense pillars of dust and gas are "dissipating", what is the nature of that dissipation? Perhaps the radiation is knocking molecules from the thin outer layers of the pillars into space at rates which somehow manages to prevent this removed mass from revealing itself?

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Re: APOD: The Fairy of Eagle Nebula (2011 Aug 21)

Postby neufer » Tue Jan 17, 2012 9:48 pm

http://www.universetoday.com/92705/the- ... more-92705 wrote:
The Eagle Nebula as You’ve Never Seen it Before
by Nancy Atkinson on January 17, 2012

<<Here’s a stunning new look deep inside the iconic “Pillars of Creation.” As opposed to the famous Hubble Space Telescope image — which shows mainly the surface of the pillars of gas and dust — this composite image from ESA’s Herschel Space Observatory in far-infrared and XMM-Newton telescope in X-rays allows astronomers to peer inside the pillars and see more detail of the structures in this region. It shows how the hot young stars detected by the X-ray observations are carving out cavities, sculpting and interacting with the surrounding ultra-cool gas and dust.

But enjoy the view while you can. The sad part is that likely, this beautiful region has already been destroyed by a supernova 6,000 years ago. But because of the distance, we haven’t seen it happen yet.

The Eagle Nebula is 6,500 light-years away in the constellation of Serpens. It contains a young hot star cluster, NGC6611, which is visible with modest back-yard telescopes. This cluster is sculpting and illuminating the surrounding gas and dust, resulting in a huge hollowed-out cavity and pillars, each several light-years long.

The Hubble image hinted at new stars being born within the pillars, deep inside small clumps known as ‘evaporating gaseous globules’ or EGGs, but because of the obscuring dust, Hubble’s visible light picture was unable to see inside and prove that young stars were indeed forming.

The new image shows those hot young stars are responsible for carving the pillars. The new image also uses data from near-infrared images from the European Southern Observatory’s (ESO’s) Very Large Telescope at Paranal, Chile, and visible-light data from its Max Planck Gesellschaft 2.2m diameter telescope at La Silla, Chile. Earlier mid-infrared images from ESA’s Infrared Space Observatory and NASA’s Spitzer, and the new XMM-Newton data, have led astronomers to suspect that one of the massive, hot stars in NGC6611 may have exploded in a supernova 6,000 years ago, emitting a shockwave that destroyed the pillars. But we won’t see the destruction for several hundred years yet.>>
Art Neuendorffer


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