APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

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APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by APOD Robot » Thu Nov 20, 2014 5:10 am

Image LDN 988: Dark Nebula in Cygnus

Explanation: Obscuring the rich starfields of northern Cygnus, dark nebula LDN 988 lies near the center of this cosmic skyscape. Composed with telescope and camera, the scene is some 2 degrees across. That corresponds to 70 light-years at the estimated 2,000 light-year distance of LDN 988. Stars are forming within LDN 988, part of a larger complex of dusty molecular clouds along the plane of our Milky Way galaxy sometimes called the Northern Coalsack. In fact, nebulosities associated with young stars abound in the region, including variable star V1331 Cygni shown in the inset. At the tip of a long dusty filament and partly surrounded by a curved reflection nebula, V1331 is thought to be a T-Tauri star, a sun-like star still in the early stages of formation.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by starsurfer » Thu Nov 20, 2014 12:40 pm

This is something I never expected to see on APOD! V1331 Cygni is one of many interesting stars associated with a nebula in this constellation, check this closeup by Adam Block. It's nice that the description also includes a link to the 2013 paper, Bo Reipurth is one of the best researchers (of many in the world) of star formation.

I think one of the first images of this region was this one by Tom Davis from 2009: http://www.tvdavisastropics.com/astroim ... 00008c.htm

However, there was an image of it prior to his by Jay McNeil (of McNeil's Nebula fame): http://www.deepskyastro.org/

Another nice image is this one by Bernhard Hubl: http://www.astrophoton.com/LDN0988.htm

Finally, someone called Judy Schmidt also processed Hubble data for V1331 Cygni: https://www.flickr.com/photos/geckzilla/11002252945/

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by BDanielMayfield » Thu Nov 20, 2014 1:09 pm

starsurfer wrote:This is something I never expected to see on APOD! V1331 Cygni is one of many interesting stars associated with a nebula in this constellation, check this closeup by Adam Block. It's nice that the description also includes a link to the 2013 paper, Bo Reipurth is one of the best researchers (of many in the world) of star formation.
Why did you never expect to see this on APOD starsurfer? Is it that images of dark clouds don't get the coverage they deserve perhaps? I note that it took all night for someone to comment about this. But I too am glad this image was provided. Following a chain of links led me to this about T-Tauri stars from the AAVSO:
About T Tauri stars

T Tauri stars are named for the prototype of the class, T Tauri. These objects are pre-main sequence stars and have recently emerged from the opaque envelope of stellar formation. Having recently coalesced from their dusty and gaseous surroundings, these stars now become visible at optical wavelengths. The clouds of dust and gas that condense are composed of mainly Hydrogen, some Helium, and some other trace elements. The clouds also contain small amounts of Lithium which is usually destroyed as the star evolves to the main sequence stage of life. Hence, Lithium is often an indicator of stellar youth. This spectral feature is seen in the atmospheres of the T Tauri stars, which implies, in the astronomical sense, that T Tauri stars are a young, low-mass stars that are contracting as they evolve toward the main sequence stage of stellar evolution. These stars often have large protoplanetary accretion disks left over from stellar formation. The general belief is that T Tauri stars are newly forming stars in the galaxy and may be growing in size through accretion. Brightness changes detected in these stars are not due to evolutionary effects, per se, but may be due to such processes as instabilities in the disk, violent activity in the atmosphere of the star, and may also be due in part to moving clouds of dust and gas from which they were conceived. "Stars with masses roughly 0.2 to three times the Sun's and with ages 100,000 to 1,000,000 years typify the T Tauri regime" (Cohen 1981).

Many of the T Tauri stars are found to reside in or near areas that are hidden by the Milky Way clouds. "We now know why this is so: those stars were born in those dark clouds, within the last 10 million years or so, and there has not been enough time for them to move very far from their birthplaces" (Herbing 1987). The Taurus-Auriga dark cloud is a known hot-bed of such stars.

Our own Sun presumably passed through the T Tauri stage some 4 1/2 billion years ago. Therefore, these stars may be able to offer us a peek into the evolution of our own Sun, solar system, as well as other planetary systems.
So people shouldn't overlook these dusty areas as of little interest. They are where new solar systems are being created.

Bruce
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by starsurfer » Thu Nov 20, 2014 2:54 pm

BDanielMayfield wrote:
starsurfer wrote:This is something I never expected to see on APOD! V1331 Cygni is one of many interesting stars associated with a nebula in this constellation, check this closeup by Adam Block. It's nice that the description also includes a link to the 2013 paper, Bo Reipurth is one of the best researchers (of many in the world) of star formation.
Why did you never expect to see this on APOD starsurfer? Is it that images of dark clouds don't get the coverage they deserve perhaps? I note that it took all night for someone to comment about this. But I too am glad this image was provided. Following a chain of links led me to this about T-Tauri stars from the AAVSO:
About T Tauri stars

T Tauri stars are named for the prototype of the class, T Tauri. These objects are pre-main sequence stars and have recently emerged from the opaque envelope of stellar formation. Having recently coalesced from their dusty and gaseous surroundings, these stars now become visible at optical wavelengths. The clouds of dust and gas that condense are composed of mainly Hydrogen, some Helium, and some other trace elements. The clouds also contain small amounts of Lithium which is usually destroyed as the star evolves to the main sequence stage of life. Hence, Lithium is often an indicator of stellar youth. This spectral feature is seen in the atmospheres of the T Tauri stars, which implies, in the astronomical sense, that T Tauri stars are a young, low-mass stars that are contracting as they evolve toward the main sequence stage of stellar evolution. These stars often have large protoplanetary accretion disks left over from stellar formation. The general belief is that T Tauri stars are newly forming stars in the galaxy and may be growing in size through accretion. Brightness changes detected in these stars are not due to evolutionary effects, per se, but may be due to such processes as instabilities in the disk, violent activity in the atmosphere of the star, and may also be due in part to moving clouds of dust and gas from which they were conceived. "Stars with masses roughly 0.2 to three times the Sun's and with ages 100,000 to 1,000,000 years typify the T Tauri regime" (Cohen 1981).

Many of the T Tauri stars are found to reside in or near areas that are hidden by the Milky Way clouds. "We now know why this is so: those stars were born in those dark clouds, within the last 10 million years or so, and there has not been enough time for them to move very far from their birthplaces" (Herbing 1987). The Taurus-Auriga dark cloud is a known hot-bed of such stars.

Our own Sun presumably passed through the T Tauri stage some 4 1/2 billion years ago. Therefore, these stars may be able to offer us a peek into the evolution of our own Sun, solar system, as well as other planetary systems.
So people shouldn't overlook these dusty areas as of little interest. They are where new solar systems are being created.

Bruce
I don't know why but certain things I don't expect to see on APOD. Other images I'm confident would be chosen for APOD never are.

I also agree that dusty dark nebulae are amazing and as well as containing low mass star formation, they are also photogenic, especially ones that obscure parts of the Milky Way. Since it would be appropriate, here is a list of some of dark nebulae I like:

LDN 673 by Adam Block: http://www.caelumobservatory.com/gallery/ldn673.shtml
Pipe Nebula by Jason Jennings: http://cosmicphotos.com/gallery/image.p ... lbum_id=11
Sandqvist 169 by Marco Lorenzi: http://www.glitteringlights.com/Images/ ... WVpcRqS/X3
B86 by Bernhard Hubl: http://www.astrophoton.com/NGC6520.htm
LDN 1003 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
Bernes 149 by Fabian Neyer: http://www.starpointing.com/ccd/bernes149.html
Coalsack Nebula by Bernhard Hubl: http://www.astrophoton.com/coalsack.htm
Serpens Cloud by Tom Davis: http://www.tvdavisastropics.com/astroim ... 000101.htm
LDN 935 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
B142 by Bernhard Hubl: http://www.astrophoton.com/B143.htm

I also like infrared views of dark clouds, which can sometimes show spectacular molecular hydrogen outflows.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Ron-Astro Pharmacist » Thu Nov 20, 2014 3:32 pm

http://www.nasa.gov/topics/universe/fea ... launt.html

I had never run across FU Ori objects before; maybe this will be identified as one someday.Thanks for introducing all the recent evidence into newly forming solar systems and the fascinating new evidence into their fields of research. It's very topical and enjoyable to be able to go out and point to Cygnus and know a little bit about something so prominent in the current night sky.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by dlw » Thu Nov 20, 2014 5:34 pm

I'm wondering why some of the molecular clouds are long and narrow. The large amorphous clouds may be left overs from major events, and perhaps coalescing, seem rather normal. The long narrow ones such as the one in which V1331 Cyg is developing and also other clouds in that area would seem to have been formed by some more distinct physical phenomena.
V1331 Cyg clouds.jpg
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Boomer12k » Thu Nov 20, 2014 6:33 pm

Awesome image...a "wall of stars"....and the proto-system is neat to see...

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by BDanielMayfield » Fri Nov 21, 2014 12:02 am

starsurfer, wow, two most excellent postings today :!: I had a most enjoyable lunch hour today perusing your favorite dark cloud images:
starsurfer wrote:... here is a list of some of dark nebulae I like:

LDN 673 by Adam Block: http://www.caelumobservatory.com/gallery/ldn673.shtml
Pipe Nebula by Jason Jennings: http://cosmicphotos.com/gallery/image.p ... lbum_id=11
Sandqvist 169 by Marco Lorenzi: http://www.glitteringlights.com/Images/ ... WVpcRqS/X3
B86 by Bernhard Hubl: http://www.astrophoton.com/NGC6520.htm
LDN 1003 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
Bernes 149 by Fabian Neyer: http://www.starpointing.com/ccd/bernes149.html
Coalsack Nebula by Bernhard Hubl: http://www.astrophoton.com/coalsack.htm
Serpens Cloud by Tom Davis: http://www.tvdavisastropics.com/astroim ... 000101.htm
LDN 935 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
B142 by Bernhard Hubl: http://www.astrophoton.com/B143.htm
:clap: :clap:
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by BDanielMayfield » Fri Nov 21, 2014 12:17 am

dlw wrote:I'm wondering why some of the molecular clouds are long and narrow. The large amorphous clouds may be left overs from major events, and perhaps coalescing, seem rather normal. The long narrow ones such as the one in which V1331 Cyg is developing and also other clouds in that area would seem to have been formed by some more distinct physical phenomena.
V1331 Cyg clouds.jpg
Good question. Why are so many molecular clouds long and narrow? There must be some common physical reason why this is such a common shape for these objects to condense into. Gravity is of course important, but there's got to be more than just gravity at work on them, or they would tend to be more spherical, I would think.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Ann » Fri Nov 21, 2014 5:05 am

BDanielMayfield wrote:
dlw wrote:I'm wondering why some of the molecular clouds are long and narrow. The large amorphous clouds may be left overs from major events, and perhaps coalescing, seem rather normal. The long narrow ones such as the one in which V1331 Cyg is developing and also other clouds in that area would seem to have been formed by some more distinct physical phenomena.
V1331 Cyg clouds.jpg
Good question. Why are so many molecular clouds long and narrow? There must be some common physical reason why this is such a common shape for these objects to condense into. Gravity is of course important, but there's got to be more than just gravity at work on them, or they would tend to be more spherical, I would think.
Wouldn't it be interesting if it had something to do with magnetism?

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by DavidLeodis » Fri Nov 21, 2014 1:10 pm

There's a lot of stars in that fascinating image! :P

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Chris Peterson » Fri Nov 21, 2014 2:46 pm

dlw wrote:I'm wondering why some of the molecular clouds are long and narrow.
I expect that the origin of these clouds lies in shells of material thrown off by cataclysmic stellar events like supernovas. That means that locally, they are originally sheet-like. We are going to see sheets as long and narrow, because only those that we observe largely end-on will be visible. In addition, over time, sheet-like structures will tend to collapse to rod-like structures and blob-like structures due to the actions of gravity.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by starsurfer » Fri Nov 21, 2014 3:01 pm

BDanielMayfield wrote:starsurfer, wow, two most excellent postings today :!: I had a most enjoyable lunch hour today perusing your favorite dark cloud images:
starsurfer wrote:... here is a list of some of dark nebulae I like:

LDN 673 by Adam Block: http://www.caelumobservatory.com/gallery/ldn673.shtml
Pipe Nebula by Jason Jennings: http://cosmicphotos.com/gallery/image.p ... lbum_id=11
Sandqvist 169 by Marco Lorenzi: http://www.glitteringlights.com/Images/ ... WVpcRqS/X3
B86 by Bernhard Hubl: http://www.astrophoton.com/NGC6520.htm
LDN 1003 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
Bernes 149 by Fabian Neyer: http://www.starpointing.com/ccd/bernes149.html
Coalsack Nebula by Bernhard Hubl: http://www.astrophoton.com/coalsack.htm
Serpens Cloud by Tom Davis: http://www.tvdavisastropics.com/astroim ... 000101.htm
LDN 935 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
B142 by Bernhard Hubl: http://www.astrophoton.com/B143.htm
:clap: :clap:
I aim to please, glad you enjoyed the images! I really like dark nebulae and in my opinion they are underrated. For next year I want to see more amateur images of dark nebulae taken with large telescopes, most images are widefield.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by geckzilla » Fri Nov 21, 2014 6:34 pm

starsurfer wrote:I aim to please, glad you enjoyed the images! I really like dark nebulae and in my opinion they are underrated. For next year I want to see more amateur images of dark nebulae taken with large telescopes, most images are widefield.
The best are the ones with glowy things inside them. The recent HL Tauri press release happened within the dark blob next to Aldebaran which you can see very easily in this APOD.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by BDanielMayfield » Sat Nov 22, 2014 12:31 am

Chris Peterson wrote:
dlw wrote:I'm wondering why some of the molecular clouds are long and narrow.
I expect that the origin of these clouds lies in shells of material thrown off by cataclysmic stellar events like supernovas. That means that locally, they are originally sheet-like. We are going to see sheets as long and narrow, because only those that we observe largely end-on will be visible. In addition, over time, sheet-like structures will tend to collapse to rod-like structures and blob-like structures due to the actions of gravity.
But is the collapse solely due to gravity? Ann raised an interesting conjecture:
Ann wrote:Wouldn't it be interesting if it had something to do with magnetism?
I think that the magnetic field strength way out in open space would be very weak. But, during the supernova events that largely create the metals forming all this dust magnetized grains of dust particles could form, and after cooling off the oppositely polarized ends of grains of dust would tend to stick together due to magnetism. Couldn't ionizing radiation also lead to charge differences that would help space dust clump together? Electrostatic forces between small particles are enormously greater than the gravitational attraction between them.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Chris Peterson » Sat Nov 22, 2014 12:36 am

BDanielMayfield wrote:But is the collapse solely due to gravity? Ann raised an interesting conjecture:
Ann wrote:Wouldn't it be interesting if it had something to do with magnetism?
I think that the magnetic field strength way out in open space would be very weak. But, during the supernova events that largely create the metals forming all this dust magnetized grains of dust particles could form, and after cooling off the oppositely polarized ends of grains of dust would tend to stick together due to magnetism. Couldn't ionizing radiation also lead to charge differences that would help space dust clump together? Electrostatic forces between small particles are enormously greater than the gravitational attraction between them.
I think the collapse is caused only by gravity. Not only are magnetic fields in open space very weak, but the material isn't really influenced by magnetism. Magnetic fields during the supernova itself may introduce structure, but I don't think we're seeing anything under the influence of magnetic fields in regions like this.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by starsurfer » Sat Nov 22, 2014 3:48 pm

geckzilla wrote:
starsurfer wrote:I aim to please, glad you enjoyed the images! I really like dark nebulae and in my opinion they are underrated. For next year I want to see more amateur images of dark nebulae taken with large telescopes, most images are widefield.
The best are the ones with glowy things inside them. The recent HL Tauri press release happened within the dark blob next to Aldebaran which you can see very easily in this APOD.
I like it when you get technical, geckzilla! :D
I presume you are referring to Herbig Haro objects and I also agree that dark clouds with them are very lovely. The nebula you are referring to is LDN 1551 with the starforming region Sh2-239, Adam Block did an amazing image of it.

Other regions with Herbig Haro objects I like are NGC 1999, NGC 6726 and NGC 1333.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by geckzilla » Sat Nov 22, 2014 6:46 pm

I like the widefield view which shows some landmark objects so that one can orient oneself and get a good idea for the scale and position. No one memorizes stuff like LDN 1551 but lots of people know where and what the Pleiades and Aldebaran are.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by geckzilla » Thu Nov 27, 2014 3:13 am

Coincidentally, I sprinkled a layer of cinnamon on top of some bubbling oatmeal a few moments ago, put the jar back in the cupboard, looked back at the oatmeal and it had formed dusty galactic filaments. No gravity or magnets required, just bubbles.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Nitpicker » Thu Nov 27, 2014 3:23 am

geckzilla wrote:Coincidentally, I sprinkled a layer of cinnamon on top of some bubbling oatmeal a few moments ago, put the jar back in the cupboard, looked back at the oatmeal and it had formed dusty galactic filaments. No gravity or magnets required, just bubbles.
Gravity drives the buoyancy forces that make the bubbles rise.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by geckzilla » Thu Nov 27, 2014 3:26 am

Ok, gravity required for the experiment to work, but it's not like gravity is what's causing the filaments to form. YOU. You know what I meant.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Nitpicker » Thu Nov 27, 2014 3:43 am

Based on Chris's comments above, regarding sheet-like structures only visible from side on, to make it a fair analogy, you'd have to observe the surface of the oatmeal from side-on. (I've decided I quite enjoy poking holes in astronomy analogies that are based on breakfast cereals. Sorry.)

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by geckzilla » Thu Nov 27, 2014 3:53 am

That wouldn't work because it's a 2d analogue.
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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by Nitpicker » Thu Nov 27, 2014 4:03 am

geckzilla wrote:That wouldn't work because it's a 2d analogue.
If the nebula is sheet-like, then the reality is 2-D. (The negligible thickness of the sheet being comparable to the negligible thickness of the cinnamon layer.)

Did you try nutmeg? Yum.

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Re: APOD: LDN 988: Dark Nebula in Cygnus (2014 Nov 20)

Post by geckzilla » Thu Nov 27, 2014 4:08 am

You've officially lost me.
Just call me "geck" because "zilla" is like a last name.