APOD: Rings Around the Ring Nebula (2014 Aug 13)

[APOD Robot]

Rings Around the Ring Nebula

Explanation: It is a familiar sight to sky enthusiasts with even a small telescope. There is much more to the Ring Nebula (M57), however, than can be seen through a small telescope. The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. This remarkable composite image includes narrowband hydrogen image, visible light emission, and infrared light emission. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from a dying, sun-like star. The Ring Nebula is about 2,000 light-years away toward the musical constellation Lyra.

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[Ann]

Congratulations, Rob, that's a great image!

Ann

[MargaritaMc]

Just a quick thank you to the editor for today's links in the Apod text.

These two especially (behind the hyperlinks in "this well-studied example of a planetary nebula" ) I found very interesting and helpful:

http://www.caha.es/the-ring-nebula.html and http://www.noao.edu/jacoby/

M

[Psnarf]

Dr. Gendler never ceases to amaze me.
Is it serendipity that the axis of this nebula points in our direction, or would the same view be visible, say, from someplace out on the X-axis?. (Z-Axis from Earth to the center, X-axis horizontal, Y-axis vertical)

[hlwelborn]

Holy Toledo !

[KarelVreeburg]

I tried before, but,... This is not a planetary Nebula. Not possible. The material is not expelled from the equator, but is ejected from the poles, south and north, Thus forming a perfect hourglass nebula. If there were planets, they are not involved in this process. I suppose you don’t believe me, but ,… If you look better you will know why, I can explain, if you want. Karel

[geckzilla]

I tried before, but,... This is not a planetary Nebula. Not possible. The material is not expelled from the equator, but is ejected from the poles, south and north, Thus forming a perfect hourglass nebula. If there were planets, they are not involved in this process. I suppose you don’t believe me, but ,… If you look better you will know why, I can explain, if you want. Karel

Planets are never involved in the formation of planetary nebulas, just like hourglasses are never involved in hourglass nebulas.

http://en.wikipedia.org/wiki/Planetary_nebula

. . . the term 'planetary nebula' is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets.

[BDanielMayfield]

I tried before, but,... This is not a planetary Nebula. Not possible. The material is not expelled from the equator, but is ejected from the poles, south and north, Thus forming a perfect hourglass nebula. If there were planets, they are not involved in this process. I suppose you don’t believe me, but ,… If you look better you will know why, I can explain, if you want. Karel

This is too a planetary nebula Karel, and yes, planets are not involved in the processes (aging stars shedding outer material) that form them. They're only called "planetary" because they can resemble a planet to a telescopic observer.

(as also explained above by Geck.)

[Boomer12k]

One of my favorite objects....and one of my best efforts to photograph.

I was quite stunned when I first saw the pictures of the outer areas of the nebula.

And this is also a GREAT SHOT OF IT! Such detail....

:---[===] *

[Boomer12k]

Maybe "Planetary Nebula"...and even "Nebula"...should be re-evaluated, and renamed...."STAR NEBULA"....or "Star Remnant"....as they are not Supernova, or Nova...but are...as pointed out...not Planets...and even "nebula" can be confusing as there are several other types...Dust...Emission...Reflection...etc.... We do say..."Supernova Remnant", not "Supernova Nebula",....so why not..."Stellar Remnant"..?

In recent years...OTHER OBJECTS have been redefined....so why not this too?

Maybe a conference at the next Symposium.....

:---[===] *

[Guest]

What we are looking at looks like rings, but we only see it from the top or the bottom. If you would see it from the side you would probably see something like the red square nebula which is an hourglass nebula http://apod.nasa.gov/apod/ap121216.html

[geckzilla]

hourglass nebula

Ok, let's explain the "hourglass nebula" as it has been mentioned twice, now. An hourglass nebula is just a way to describe any nebula which is shaped like an hourglass, which may not even refer to a planetary nebula. It is not a classification of nebulas. Many hourglass shaped nebulas are young planetary nebulas in which we observe the early stages of a planetary nebula's development. The hourglass shape is caused by two collimated outflows which are often (but not always) symmetrical in shape.

You can suppose that the Ring Nebula looks like the Red Rectangle when viewed from another angle but such assumptions should be taken with a grain of salt. It is very hard to measure the distance to individual pieces of the nebula and therefore very difficult to construct a three-dimensional image of the thing. Nonetheless, some clever sleuthing work has been done in an effort to do just this, and it has not been described as hourglass shaped. Have a look.

Not an hourglass.

AstroBob explains

Spacetelescope.org article

Actual paper full of science in all of its confounding glory

[bystander]

Actual paper full of science in all of its confounding glory

There are actually three papers:

1. Studies of NGC 6720 with Calibrated HST/WFC3 Emission-line Filter Images.
2. Structure and Evolution
   http://adsabs.harvard.edu/abs/2013AJ....145...92O
   http://dx.doi.org/10.1088/0004-6256/145/4/92
   http://arxiv.org/abs/1301.6636
3. Physical Conditions
   http://adsabs.harvard.edu/abs/2013AJ....145...93O
   http://dx.doi.org/10.1088/0004-6256/145/4/93
   http://arxiv.org/abs/1301.6642
4. Tangential Motions using AstroDrizzle Images
   http://adsabs.harvard.edu/abs/2013AJ....145..170O
   http://dx.doi.org/10.1088/0004-6256/145/6/170
   http://arxiv.org/abs/1304.5233

[geckzilla]

Thanks, I didn't include the second or third because they didn't deal so much with the structure.

[bystander]

Yeah, but they are full of science in all of its confounding glory.

[geckzilla]

Emphasis on the confounding part.

[starsurfer]

This is one of the few planetary nebulae known to have a double halo, one other well known example is NGC 2438. Haloes are actually quite common and represent the AGB mass loss of the progenitor star. I'm currently obsessed with them! Also the one around M57 also contains OIII emission but isn't seen in this image.

[owlice]

Emphasis on the confounding part.

lol!!

[Karel Vreeburg]

It seems nobody is listening, Your problem,.. "Rings" like this are expressions of polar expulsions of matter. I don’t mind if before we were wrong because we did not understand. Now with better 3-D knowledge we should be aware that things we see are not the things that we see. If hourglass is the best word , I don’t know. But polar Precession jets YES. Remnants caused by circular polar Jets. Which to my opinion always result into hourglass Nebula. Even big star galaxies behave like this. http://apod.nasa.gov/apod/ap121205.html Look, Think Decide. Even in big galaxies there is a precession of polar axes. If there is not such a movement images like this would be impossible. Karel

[geckzilla]

Karel, just because you failed to convince me doesn't mean I didn't listen to you. I think you are wrong and I cited some reasons why. If there is some kind of research with results contrary to the research I noted, you should let us see it. Otherwise I have to assume this is your own home-brew theory.

[starsurfer]

It seems nobody is listening, Your problem,.. "Rings" like this are expressions of polar expulsions of matter. I don’t mind if before we were wrong because we did not understand. Now with better 3-D knowledge we should be aware that things we see are not the things that we see. If hourglass is the best word , I don’t know. But polar Precession jets YES. Remnants caused by circular polar Jets. Which to my opinion always result into hourglass Nebula. Even big star galaxies behave like this. http://apod.nasa.gov/apod/ap121205.html Look, Think Decide. Even in big galaxies there is a precession of polar axes. If there is not such a movement images like this would be impossible. Karel

I think you're trying to say something scientifically valid but maybe not expressing yourself in the correct way. However there are a few known examples of planetary nebulae with jets, see below:

Fg 1: http://www.eso.org/public/images/eso1244a/
Copyright: ESO

Click to view full size image

ETHOS 1: http://www.capella-observatory.com/Imag ... ETHOS1.htm
Copyright: Stefan Binnewies and Josef Pöpsel

Click to view full size image

There are other examples such as Abell 63 and Longmore 16.


Also the so-called "rings" you refer to are the outer halo of the planetary nebula, this is produced before the original star moves onto the planetary nebula phase.

Finally, you are right that our two-dimensional perspective of three-dimensional structures are not the same but astronomers can now do a good job at figuring out the 3D structure of a planetary nebula.