APOD: Globules in the Running Chicken Nebula (2014 Mar 05)

[APOD Robot]

Globules in the Running Chicken Nebula

Explanation: The eggs from this chicken may form into stars. The above pictured emission nebula, cataloged as IC 2944, is called the Running Chicken Nebula for the shape of its greater appearance. The image was taken recently from Siding Spring Observatory in Australia and presented in scientifically assigned colors. Seen near the center of the image are small, dark molecular clouds rich in obscuring cosmic dust. Called Thackeray's Globules for their discoverer, these "eggs" are potential sites for the gravitational condensation of new stars, although their fates are uncertain as they are also being rapidly eroded away by the intense radiation from nearby young stars. Together with patchy glowing gas and complex regions of reflecting dust, these massive and energetic stars form the open cluster Collinder 249. This gorgeous skyscape spans about 70 light-years at the nebula's estimated 6,000 light-year distance.

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[Nitpicker]

Thank you. Very striking. I look at that part of the sky all the time, and I never knew that was there. I must try to photograph it and see if I can make it look like I don't have dust on the sensor.

[Boomer12k]

Interesting...I like Globules....

Very "Swirly"...and wispy.

Nice Pic...

:---[===] *

[Coil_Smoke]

I know how sensitive the site administrators get when someone wants to discuss something they feel is outside of mainstream. In poster's defense I feel much of astrophysics is speculation. I hope this does not violate forum rules about posting . I have felt for a long time that Bok's Globules (Not sure about the spelling of Bok) and the "Pillars of Creation" are bi-products of stellar formation. Could they be clouds of dust and smoke expelled by stars when they first "Ignite" ? I have been looking at these for years and usually spot a star at the leading edge of these clouds. I figure stars that condense from hydrogen atoms will not produce these features. Stars that contain rock, metals, dust and other nebular contents would tend to vaporize those materials and expel "Pillars Of Pollution" when they reach the stage of first fusion.

[neufer]

I have felt for a long time that Bok's Globules (Not sure about the spelling of Bok) and the "Pillars of Creation" are bi-products of stellar formation. Could they be clouds of dust and smoke expelled by stars when they first "Ignite" ?

It is presumed that Herbig–Haro objects are the
clouds of dust and smoke expelled by stars when they first "Ignite":

• http://apod.nasa.gov/apod/ap140204.html
  http://apod.nasa.gov/apod/ap131128.html
  http://apod.nasa.gov/apod/ap131010.html

[zbvhs]

What happens to the material in globules when it's eroded away? The "eroded away" reference describes gas as evaporating. What are the mechanisms involved?

[Keyman]

...in scientifically assigned colors

Is there a 'convention' of some kind that has decided/adopted what colors are assigned to specific...I guess, specific elements?

[Chris Peterson]

What happens to the material in globules when it's eroded away? The "eroded away" reference describes gas as evaporating. What are the mechanisms involved?

It just disperses. The local escape velocity associated with self gravitation is very low in these clouds; it doesn't take much energy to break them up.

[Chris Peterson]

...in scientifically assigned colors

Is there a 'convention' of some kind that has decided/adopted what colors are assigned to specific...I guess, specific elements?

There are a number of popular color mapping schemes. One of the most popular is called the Hubble palette, which maps SII to red, Ha to green, and [OIII] to blue.

I've got to say, "scientifically assigned colors" is a pretty poor way of describing this.

[neufer]

<<An evaporating gas globule or EGG is a region of hydrogen gas in outer space approximately 100 astronomical units in size, such that gases shaded by it are shielded from ionizing UV rays. Dense areas of gas shielded by an evaporating gas globule can be conducive to the birth of stars. Evaporating gas globules were first conclusively identified via photographs taken by the Hubble Space Telescope in 1995.

EGG's are the likely predecessors of new protostars. Inside an EGG the gas and dust are denser than in the surrounding dust cloud. Gravity pulls the cloud even more tightly together as the EGG continues to draw in material from its surroundings. As the cloud density builds up the globule becomes hotter under the weight of the outer layers, a protostar is formed inside the EGG.

A protostar may have too little mass to become a star. If so it becomes a brown dwarf. If the protostar has sufficient mass, the density reaches a critical level where the temperature exceeds 10 million degrees kelvin at its center. At this point, a nuclear reaction starts converting hydrogen to helium and releasing large amounts of energy. The protostar then becomes a star and joins the main sequence on the HR diagram.>>

What happens to the material in globules when it's eroded away?
The "eroded away" reference describes gas as evaporating. What are the mechanisms involved?

It just disperses.
The local escape velocity associated with self gravitation is very low in these clouds;
it doesn't take much energy to break them up.

<<How are the interstellar grains destroyed? There are several ultraviolet processes which lead to grain "explosions" for tiny grains. More prominent for interstellar dust grains is sputtering erosion when energetic atoms or ions pierce the surface of a solid to deposit enough energy to cause secondary ions to be ejected from the resulting internal explosion of fast ions. This causes total mass to be sputtered away with a mean lifetime 2-4x10⁸ years.>>

[Chris Peterson]

<<How are the interstellar grains destroyed? There are several ultraviolet processes which lead to grain "explosions" for tiny grains...

In reality, however, very little dust erosion like this occurs. Most of the mass is simply dispersed, substantially unaltered.

[neufer]

---

This mid-infrared image of the W40 star-forming region of the Milky Way galaxy was captured recently by the FORCAST instrument on the 100-inch telescope aboard the SOFIA flying observatory. (NASA / FORCAST image)

See: http://annesastronomynews.com/photo-gal ... louds/w40/

[CURRAHEE CHRIS]

Very inspiring picture and captivating but I just dont see a running chicken when I look at the picture I really dont see anything I can easily describe.

[Indigo_Sunrise]

Just so I'm clear: Bok Globules and Thackeray Gobules are the same thing?
The link for Thackeray's Globules in the description has this:

Astronomer A.D. Thackeray first spied the globules in IC 2944 in 1950. Globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947

I'm just asking for clarification that either name for the objects is correct.
TIA


*And very nice image today!

[Chris Peterson]

Very inspiring picture and captivating but I just dont see a running chicken when I look at the picture :( I really dont see anything I can easily describe.

Google it and you can see a number of annotated images with different opinions about where the chicken is. Keep in mind that high resolution, narrowband images almost always obliterate whatever broad structure originally gave a nebula its name.

[Ann]

What I find most interesting about the Running Chicken Nebula is the cluster that lights it up, Collinder 249. According to my software, Collinder 249 contains five O-type stars, HD 101131, HD 101190, HD 101205, HD 101298, and HD 101436. Five O-type stars is a lot in a cluster that looks sort of sparse, I think.

Fascinating!

Ann

[rstevenson]

... I feel much of astrophysics is speculation. ... I have felt for a long time that Bok's Globules (Not sure about the spelling of Bok) and the "Pillars of Creation" are bi-products of stellar formation. Could they be clouds of dust and smoke expelled by stars when they first "Ignite" ?...

So you have "felt for a long time" that something is true, while you dismiss as "speculation" much of the science that others have worked so hard to figure out. That seems a poor way to understand something as non-obvious as Bok globules -- or anything else, for that matter.

A glance at the Bok globule wikipedia page tells me...

Bok globules are dark clouds of dense cosmic dust and gas in which star formation sometimes takes place. ... Bok globules that are blasted by nearby stars exhibit fragmentation of materials to produce a tail.

In short, your feelings are likely leading you astray.

Rob

[Anthony Barreiro]

Okay, but which came first, the Running Chicken nebula, or the Eroding Gas Globules (EGG's)?

[LocalColor]

Great image. Would like to know more about what equipment the astrophotographer used. Can't find any info on the photo at his website (great website too!)

[CURRAHEE CHRIS]

Very inspiring picture and captivating but I just dont see a running chicken when I look at the picture I really dont see anything I can easily describe.

Google it and you can see a number of annotated images with different opinions about where the chicken is. Keep in mind that high resolution, narrowband images almost always obliterate whatever broad structure originally gave a nebula its name.

Thanks Chris!! I did just as you suggested and saw it laid out. Definately would not have seen it no matter how creative I tried to get.

[Ann]

Very inspiring picture and captivating but I just dont see a running chicken when I look at the picture I really dont see anything I can easily describe.

Click to view full size image

Photo: Mario Cogo

You can see the Running Chicken Nebula here.

The round head of the chicken is at upper right. The chicken is looking down, and its open bill is pointing down. The chicken has got an eye in the middle of its head.

One clumsy Donald Duck foot is protruding to the lower right. The other foot is missing.

At upper center is what looks like one raised wing, as if the chicken was flapping its wings as it is running. Above the chicken's head is what might be the the other wing.

The rest of the nebula is the chicken's round, well-fed body.

The bright star in the middle of the chicken's body is Lambda Centauri. This is a foreground star, not part of the cluster that ionizes the nebula.

The full Running Chicken Nebula is quite big. Today's APOD is a small part of the full nebula. Take a look at this picture. The bright star at upper right is Lambda Centauri. Tody's APOD is centered on the small group in the middle of the picture that I just gave you a link to. Note the small Bok globules floating around there.

Finally, take a look at this APOD from 2010. The Running Chicken Nebula is at lower left, and it appears to be "chasing" the large Carina Nebula at upper right.

Ann

[Nitpicker]

I must try to photograph it and see if I can make it look like I don't have dust on the sensor.

Not quite as easy as I had imagined. Last night, I confirmed that my (limited Alt-Az) system is going to require more than 5x30s worth of stretched signal, possibly including some IR, before Thackeray's Globules (examples of Bok globules) will show up sufficiently well, for anyone to say "ooh ahh" at them. I will spare you all the slightly darker patches of ugly noise I have imaged thus far.

[Chris Peterson]

You can see the Running Chicken Nebula here...

If you say so. All I see is the Squirrel Roadkill Nebula.

[neufer]

You can see the Running Chicken Nebula here...

• . http://apod.nasa.gov/apod/ap080418.html

[Beyond]

I don't really see much chicken now-a-days either. I think Larry and his brother Daryl and his other brother Daryl got into Astronomy and are picking everything clean.