APOD: Dust of the Orion Nebula (2015 Dec 29)

[APOD Robot]

Dust of the Orion Nebula

Explanation: What surrounds a hotbed of star formation? In the case of the Orion Nebula -- dust. The entire Orion field, located about 1600 light years away, is inundated with intricate and picturesque filaments of dust. Opaque to visible light, dust is created in the outer atmosphere of massive cool stars and expelled by a strong outer wind of particles. The Trapezium and other forming star clusters are embedded in the nebula. The intricate filaments of dust surrounding M42 and M43 appear brown in the featured image, while central glowing gas is highlighted in red. Over the next few million years much of Orion's dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy.

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[Ann]

That is a very fine picture! And congratulations to Raul Villaverde Fraile, who is an excellent astrophotographer!

The colors of this image are subtle and many-hued. Over much of the image there is a "background" of red Ha emission, caused both by all the ultraviolet photons pumped out by the bright stars in the region and, I think, by the general "stormy condition" in the area. But the Ha emission is very red and bright only in the Orion Nebula itself. Not in the Trapezium though, which is bright with all kinds of emission, including OIII.

The dust is pervasive. It is interesting to see how a thick cocoon of dust appears to keep the red nebulosity of the Orion Nebula enclosed. But some of the blue starlight from the hot stars in the Trapezium escapes the enclosure and colors parts of the tattered and broken dust barrier bluish. The bluest reflection nebulosity dust is found in the (much "calmer" and less tattered) Running Man Nebula, where there is an underlying background of deep magenta, a mixture of emission and reflection nebulosity. But with no dust, there is no reflection nebulosity, so wherever you see patches of blue that are not simply "photographic halos", there is dust. Of course all the huge swaths of brown are made of dust, too.

We expect a site of star formation to be dusty. In our nearby, evolved universe, star formation is almost always (and perhaps absolutely always) associated with dust. Clouds of gas contract under their own gravity, and the dust they contain helps them contract and cool, which is necessary for star formation. But star formation in itself produces more dust, and high-mass stars like the brilliant stars in Orion produce a lot of dust (sometimes copious amounts of it) both at the beginning and at the end of their lives.

Ann

[Boomer12k]

What a spectacular image!!
My favorite deep space object. And now I have to get out my broom and sweep away the dust....SHEESH!!!!! The work just keep piling up....Aah ah ahhhhhh....CHOOOOO!!!!!!!

:---[===] *

[DesertNative]

What is / are the chemical composition(s) of nebular dust? Where did the dust originate?

[Chris Peterson]

What is / are the chemical composition(s) of nebular dust? Where did the dust originate?

Mostly silicates, with some carbonates. It originated inside stars, scattered when they shed their outer layers or when they exploded in supernovas.

[starsurfer]

What is / are the chemical composition(s) of nebular dust? Where did the dust originate?

Mostly silicates, with some carbonates. It originated inside stars, scattered when they shed their outer layers or when they exploded in supernovas.

We are stardust!

[neufer]

What is / are the chemical composition(s) of nebular dust? Where did the dust originate?

Mostly silicates, with some carbonates. It originated inside stars, scattered when they shed their outer layers or when they exploded in supernovas.

<<In circumstellar dust, astronomers have found molecular signatures of CO, silicon carbide [SiC], amorphous silicate, polycyclic aromatic hydrocarbons, water ice, and polyformaldehyde, among others (in the diffuse interstellar medium, there is evidence for silicate and carbon grains).

The large grains in interstellar space are probably complex, with refractory cores that condensed within stellar outflows topped by layers acquired subsequently during incursions into cold dense interstellar clouds. That cyclic process of growth and destruction outside of the clouds has been modeled to demonstrate that the cores live much longer than the average lifetime of dust mass. Those cores mostly start with silicate particles condensing in the atmospheres of cool oxygen rich red-giant stars and carbon grains condensing in the atmospheres of cool carbon stars. The red-giant stars have evolved off the main sequence and have entered the giant phase of their evolution and are the major source of refractory dust grain cores in galaxies. Those refractory cores are also called Stardust, which is a scientific term for the small fraction of cosmic dust that condensed thermally within stellar gases as they were ejected from the stars. Several percent of refractory grain cores have condensed within expanding interiors of supernovae, a type of cosmic decompression chamber. And meteoriticists that study this refractory stardust extracted from meteorites often call it presolar grains, although the refractory stardust that they study is actually only a small fraction of all presolar dust. Stardust condenses within the stars via considerably different condensation chemistry than that of the bulk of cosmic dust, which accretes cold onto preexisting dust in dark molecular clouds of the galaxy. Those molecular clouds are very cold, typically less than 50K, so that ices of many kinds may accrete onto grains, perhaps to be destroyed later. Finally, when the Solar System formed, interstellar dust grains were further modified by chemical reactions within the planetary accretion disk. So the history of the complex grains in the early Solar System is complicated and only partially understood.>>

<<While rare on Earth, silicon carbide [SiC] is remarkably common in space. It is a common form of stardust found around carbon-rich stars, and examples of this stardust have been found in pristine condition in primitive (unaltered) meteorites. The silicon carbide found in space and in meteorites is almost exclusively the beta-polymorph. Analysis of SiC grains found in the Murchison meteorite, a carbonaceous chondrite meteorite, has revealed anomalous isotopic ratios of carbon and silicon, indicating an origin from outside the solar system; 99% of these SiC grains originate around carbon-rich asymptotic giant branch stars. SiC is commonly found around these stars as deduced from their infrared spectra.>>

[MarkBour]

I thought I'd take a moment here at year's end to say thanks to those of you who make this site so special. Of course, first of all, Robert Nemiroff and Jerry Bonnell, who tirelessly gather these wonderful images, and share their knowledge to describe them. Next, thanks to all of those amazing people whose images/videos/projects have been featured. But third, and in my case, just as vital, to a few very knowledgeable and regular contributors who have taught me quite a bit. Chris, Art, and Ann, I see all three of you have taken time out from your holidays to come view and comment on today's image. Many times, an APOD which has only aroused a passing glance from me upon first viewing it, has quite come to life thanks to your discussions. And certainly, many of my questions have been answered by your efforts. Also, thanks to bystander, geckzilla, and owlice for your work administering the forums.

I hope you all have a healthy and prosperous 2016, and that you continue to have the time to provide this wonderful resource, sharing your knowledge and analytic skill for all to learn from. Thanks again!

[alcarreño]

I am very happy that this image was selected and annotated by you.
I wish you all a happy 2016.
Cheers
Raul Villaverde Fraile

[DavidLeodis]

I am very happy that this image was selected and annotated by you.
I wish you all a happy 2016.
Cheers
Raul Villaverde Fraile

I don't seem able to get the annotated version so I would be grateful if someone could please let me know where it can be found. Thanks.

[alcarreño]

I am very happy that this image was selected and annotated by you.
I wish you all a happy 2016.
Cheers
Raul Villaverde Fraile

I don't seem able to get the annotated version so I would be grateful if someone could please let me know where it can be found. Thanks.

You mean this ??

http://apod.nasa.gov/apod/ap151229.html

[DavidLeodis]

I am very happy that this image was selected and annotated by you.
I wish you all a happy 2016.
Cheers
Raul Villaverde Fraile

I don't seem able to get the annotated version so I would be grateful if someone could please let me know where it can be found. Thanks.

You mean this ??

http://apod.nasa.gov/apod/ap151229.html

Thanks for your help alcarreño . That link however only brings up the APOD without any annotation available. It seems that my failure to get an annotated version must be a problem with my system.

[Chris Peterson]

I am very happy that this image was selected and annotated by you.
I wish you all a happy 2016.
Cheers
Raul Villaverde Fraile

I don't seem able to get the annotated version so I would be grateful if someone could please let me know where it can be found. Thanks.

I don't believe this image has been annotated in the way we usually mean here, with an overlay identifying objects. I suspect that the term "annotate" was used instead of "notate", in reference to the caption.

[DavidLeodis]

I am very happy that this image was selected and annotated by you.
I wish you all a happy 2016.
Cheers
Raul Villaverde Fraile

I don't seem able to get the annotated version so I would be grateful if someone could please let me know where it can be found. Thanks.

I don't believe this image has been annotated in the way we usually mean here, with an overlay identifying objects. I suspect that the term "annotate" was used instead of "notate", in reference to the caption.

Thanks Chris . That does seem very likely. In any event it is though a superb image by Raul .

[owlice]

Thank you, Mark! A wonderful new year to you, too!!