APOD: The Fox Fur Nebula (2015 Dec 30)

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APOD: The Fox Fur Nebula (2015 Dec 30)

Post by APOD Robot » Wed Dec 30, 2015 5:09 am

Image The Fox Fur Nebula

Explanation: This interstellar canine is formed of cosmic dust and gas interacting with the energetic light and winds from hot young stars. The shape, visual texture, and color, combine to give the region the popular name Fox Fur Nebula. The characteristic blue glow on the left is dust reflecting light from the bright star S Mon, the bright star just below the top edge of the featured image. Textured red and black areas are a combination of the cosmic dust and reddish emission from ionized hydrogen gas. S Mon is part of a young open cluster of stars, NGC 2264, located about 2,500 light years away toward the constellation of the Unicorn (Monoceros).

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Ann » Wed Dec 30, 2015 8:17 am

That's a fine picture! :D
The Christmas Tree cluster. Photo: ESO.
This general area, the Christmas Tree cluster, is one of my favorite sites of star formation in the sky. The Fox Fur Nebula is a part of the Christmas Tree cluster, but the Fox Fur is not easy to understand.
Wikipedia wrote:
This enigmatic formation of gas and dust...
Enigmatic is the word. If Wikipedia can't shed much light on it, how can I? But at least I can show you a few pictures of this area and tell you what I see in them.

First off, in today's APOD the Fox Fur Nebula is rather brightly red at the same time as it is obviously very dusty. That in itself is strange. As a rule, dust structures either reflect the light of stars back at us, in which case they are usually bluish, or they block light from us, in which case they are brown or black. Ionized gas, on the other hand, is usually red. So why would a very dusty structure like the Fox Fur Nebula be extra red???

A clue can be found in the ESO image of the Christmas Tree cluster that I posted at left. Anyone who recognizes the Cone Nebula should be able to spot it at bottom left. But where is the Fox Fur Nebula? It is located at upper right in the image, and as you can see, it is rather dark. The bluish reflection nebula below it is much brighter. The reflection nebula is lit up by a small cluster of young stars of spectral class B, which are not hot enough to ionize a red emission nebula, but whose blue light is scattered in the dust around them and reflected back at us. The ESO picture shows us that the Fox Fur Nebula is about the same rather dark red color as much of the rest of this area. So the difference between the blue reflection nebula and the red Fox Fur nebula is not so much that the Fox Fur is so anomalously red, but rather that the reflection nebula is so bright. It is in fact likely that there is red light inside the blue reflection nebula too, but it is "drowned out" by the scattered bright blue starlight there. So why isn't the Fox Fur Nebula bright blue too from reflected starlight? Because dust doesn't just reflect but also blocks starlight, and the dust in the Fox Fur Nebula blocks most of the blue light from the nearby reflection nebula.
The Christmas Tree Cluster. Image: Davide de Martin.
Let's look at another picture of the same area. This picture is oriented "upside down" relatively to the ESO image I posted earlier, so the Cone Nebula is at top. Also the color balance is different. The blue light is quite bright here, but the red light is rather muted and dull. Where is the Fox Fur Nebula? It is to the left of the bright star, S Mon or 15 Mon. In this picture, the Fox Fur nebula looks quite "thin". The blue light in the area is shining right through it. The Fox Fur nebula now looks quite a bit like the famous "Pillars of Creation", interconnected dark dusty outlines which fade out "at the bottom", where they slowly disappear into the background. I think it is true that much of the Fox Fur is quite "thin".

On the page where I found this picture, it says:
The Fox Fur Nebula has a strange shape originate from fine interstellar dust reacting in complex ways with the energetic light and hot gas being expelled by the young stars.
The English here isn't perfect, but I agree with the message: The Fox Fur is being sculpted by energetic light coming from different directions from several stars in the area, and it is reacting to it in complex ways.
The Christmas Tree Cluster. Photo: R. Jay GaBany.

I'd like to show you one more picture of the same area. In this one, you find the Cone Nebula at right and the Fox Fur Nebula at left.

The Fox Fur is looking very foxy here! Very elegant! But you can see that it is "thin". Blue light is shining through much of it.

In the right half of the image, however, there is a lot of yellow light peeking through. I'd say that is light associated with star formation. The dust in this part of the Christmas Tree cluster region is "thick", and new stars are forming there.
The Christmas Tree Cluster. Image credit: SIRTF/NASA/ESA
I can't resist showing you one more picture. This is an infrared image of the Christmas tree cluster. The Cone Nebula is at top, right above the bright pink-looking star. (The Cone Nebula sports a bright, but not brilliant, yellow-white "head".)

All the pink lights here are baby stars in various stages of formation. Most if not all are probably quite invisible in optical images.

Where is the Fox Fur Nebula? It is all but invisible. It is at lower left, below the large cavity which is blurrily lit up by pink light. But as I said, you can barely see the Fox Fur Nebula here.

We can draw a few conclusions. The Fox Fur Nebula is "thin". There is no star formation going on inside it at all. Its nature might be slightly similar to the Pillars of Creation, except that, unlike the Pillars of Creation, it is not a site of star formation. The Fox Fur Nebula consists of gas and dust, and the dust is being buffeted by strong stellar winds from different directions. Its color comes from the diffuse Ha emission which fills much of the entire region, but the Fox Fur Nebula is not particularly bright.

That's what I can say about it, I think.

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Boomer12k » Wed Dec 30, 2015 2:43 pm

This is an awesome image to me... Shows it is carved out of a larger complex, with stars and their winds blowing open a "cavern" above it...(in this picture angle). :ssmile:

THANKS ANN for you take...

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Ron-Astro Pharmacist » Wed Dec 30, 2015 2:50 pm

A dust particle forming suggests a higher order of organization which seemingly violates the Second Law of Thermodynamics. I suspect cosmologists have many theories on how dust particles form. At some point gravity, a force in an awkward state of conjecture, would also come into play. At the endpoint - gas and solid particles form into systems resulting in us. The universe unleashes processes that should keep our curious minds busy for many years to come. The dust itself even has been placed at the center of even more fascinating study involving the thermodynamics that keeps us going
Energizer Bunny Final.jpg
and going and going. Until the fox...
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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by vanessa » Wed Dec 30, 2015 3:11 pm

The caption says, "The characteristic blue glow on the left..." but do you suppose it should say the blue glow near the top? There isn't a lot of blue glow on the left. Plus, S Mon is near the top, so it seems it would be reflecting off dust near it and creating the blue glow at the top of the image.

Thanks!

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Dad is watching » Wed Dec 30, 2015 3:13 pm

We had a question about all of the nebula photos that appear on APOD. Do all of these amazing nebula exist inside, or close to, our own galaxy?

Also, we agree that the origin of dust is a mystery just now. We have no idea where ours comes from. But we have a whole bunch of the stuff that we are ready to donate to the formation of a new planet. (Just kidding... Happy new Year)

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Chris Peterson » Wed Dec 30, 2015 3:59 pm

Ron-Astro Pharmacist wrote:A dust particle forming suggests a higher order of organization which seemingly violates the Second Law of Thermodynamics.
It is a common misunderstanding of the Second Law of Thermodynamics to assume that systems can't move in the direction of higher organization. This rule only applies to closed systems, which we clearly do not have in many places.
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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Ron-Astro Pharmacist » Wed Dec 30, 2015 5:56 pm

Chris Peterson wrote:
Ron-Astro Pharmacist wrote:A dust particle forming suggests a higher order of organization which seemingly violates the Second Law of Thermodynamics.
It is a common misunderstanding of the Second Law of Thermodynamics to assume that systems can't move in the direction of higher organization. This rule only applies to closed systems, which we clearly do not have in many places.
I think that’s why it seems confusing to me. Within a gravitationally bound system entropy exists but outside of gravity's strong influence dark energy appears to dominate the universe. Where is the boundary? I can find articles too difficult for me to fully grasp so any insight is appreciated. Is it due to the weakness of gravity as a force or other stronger forces causing particles to aggregate?

Thanks Chris.
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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Chris Peterson » Wed Dec 30, 2015 6:04 pm

Ron-Astro Pharmacist wrote:
Chris Peterson wrote:
Ron-Astro Pharmacist wrote:A dust particle forming suggests a higher order of organization which seemingly violates the Second Law of Thermodynamics.
It is a common misunderstanding of the Second Law of Thermodynamics to assume that systems can't move in the direction of higher organization. This rule only applies to closed systems, which we clearly do not have in many places.
I think that’s why it seems confusing to me. Within a gravitationally bound system entropy exists but outside of gravity's strong influence dark energy appears to dominate the universe. Where is the boundary? I can find articles too difficult for me to fully grasp so any insight is appreciated. Is it due to the weakness of gravity as a force or other stronger forces causing particles to aggregate?
There is no boundary (and entropy "exists" everywhere). For the most part, outside the Universe itself, there are no closed systems. Any system which is receiving energy can (and often does) adopt a more ordered state.

Particle aggregation generally begins with electromagnetic processes, and only switches to gravitational processes once the particles reach a certain mass. But gravity is what brings together the vast clouds of gas that keeps together the dust we see in images like this. Remember, as impressive as the dust seems, it probably doesn't represent even 1% of the mass of the entire nebula, which is mainly hydrogen.
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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Ann » Wed Dec 30, 2015 7:04 pm

Dad is watching wrote:We had a question about all of the nebula photos that appear on APOD. Do all of these amazing nebula exist inside, or close to, our own galaxy?

Also, we agree that the origin of dust is a mystery just now. We have no idea where ours comes from. But we have a whole bunch of the stuff that we are ready to donate to the formation of a new planet. (Just kidding... Happy new Year)
Happy New Year to you, too! :D

Most nebulas that appear in APODs are inside our own galaxy. The Fox Fur Nebula and Christmas Tree Nebula are certainly inside our own galaxy. According to Wikipedia, the distance to the Fox Fur Nebula is ~2600 light years. In view of the fact that our galaxy is believed to be at least 100,000 light years in diameter, a distance of 2600 light years is really pretty close.
The Tarantula Nebula in the Large Magellanic Cloud.
Photo: Tom Matheson.
But there are some famous nebulas in other galaxies, too. Our satellite galaxy, the Large Magellanic Cloud, located about 200,000 light-years away, sports an enormous and frequently photographed nebula, the Tarantula Nebula.

Many other, more distant galaxies also contain giant nebulas that can easily be photographed from the Earth. One such galaxy is M101, located about 21 million light-years away.

As for the origin of dust, I'll let others discuss whether or not it is a mystery.

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Chris Peterson » Wed Dec 30, 2015 7:38 pm

Dad is watching wrote:Also, we agree that the origin of dust is a mystery just now. We have no idea where ours comes from.
Well, we actually know in rich detail where the material comprising the dust comes from, and while it remains an area of active study, we also know a great deal about the various mechanisms involved in dust aggregation. So, no, this really doesn't qualify as a "mystery".
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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Foxy » Wed Dec 30, 2015 9:55 pm

Too bad it's not in Vulpecula!

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Re: APOD: The Fox Fur Nebula (2015 Dec 30)

Post by Ron-Astro Pharmacist » Thu Dec 31, 2015 4:50 pm

Chris Peterson wrote:
Particle aggregation generally begins with electromagnetic processes, and only switches to gravitational processes once the particles reach a certain mass. But gravity is what brings together the vast clouds of gas that keeps together the dust we see in images like this. Remember, as impressive as the dust seems, it probably doesn't represent even 1% of the mass of the entire nebula, which is mainly hydrogen.
I'll mirror Mark and Owlice's sentiment in appreciation of the time spent answering our laymans' questions. There aren't many sites so well run providing access to the assets of the contributors to Starship Asterisk* :clap:
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