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APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 3:54 am
by APOD Robot
Halo of the Cats Eye
Explanation: The
Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae
in the sky. Its haunting
symmetries are seen in the very central region of
this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three
light-years across, which surrounds the brighter, familiar
planetary nebula. Made with data from the
Nordic Optical Telescope in the
Canary Islands, the composite picture shows extended emission from the nebula.
Planetary nebulae have long been appreciated as a final phase
in the life of a sun-like star. Only much more recently however, have some planetaries been
found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the
planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the
outer filamentary portions of this halo to be 50,000 to 90,000 years.
[/b]
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 4:46 am
by Benbrilling
I see naked people around the edges. Especially in the top-left. Are you sure this isn't from an art gallery?
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 6:00 am
by Hofi
Congratulations to this beautiful immage! I really like it.
Currently, I have the Cat's Eye Nebular by Hubble hanging in my room. But I deliberate to change it into this one!
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 11:21 am
by Astronut
WOW!! to me it looks more like the birth of an Ocular Being, then a cats eye.
So I'll raise one of these
![Beer :b:](./images/smilies/beer.gif)
and say - "heres looking at YOU-kid.
![Smile :)](./images/smilies/icon_smile.gif)
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 12:36 pm
by gravi
Amazing picture! Nice start my sunday with this!
I always stop some time to see Cats Eye nebula related pictures; but I didnt knew it has a halo, and so expanded like that
Sry if this is a noob question but, if those are false colors what true colors it would be?
Have a nice day~
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 1:10 pm
by Hofi
gravi wrote:if those are false colors what true colors it would be?
You cannot say exactly! Humans would see it gray because the colors are so faint that our eyes would not recognize it.
Just have a look at this website
here. It probably will answer your question.
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 1:30 pm
by wonderboy
Benbrilling wrote:I see naked people around the edges. Especially in the top-left. Are you sure this isn't from an art gallery?
I think I can kind of see what ur talking about, like a guy standing with his arms by his side. Either way, its wierd. stop it!
Paul.
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 1:58 pm
by neufer
Hofi wrote:gravi wrote:if those are false colors what true colors it would be?
You cannot say exactly! Humans would see it gray because the colors are so faint that our eyes would not recognize it.
Just have a look at this website
here. It probably will answer your question.
http://antwrp.gsfc.nasa.gov/apod/ap070629.html
http://antwrp.gsfc.nasa.gov/apod/ap080322.html
http://www.donaldedavis.com/2002_addons/DEEPCLRS.html wrote:
![Image](http://www.donaldedavis.com/PARTS/CATSEYE2.jpg)
Don Davis: <<This HST photo is of NGC 6543, the 'Cat's eye' nebula. The initially released version is at the left.
To the right is my attempt to 'bring back' something closer to the actual colors as can be photographed from ground based telescopes. The April 1995 Sky and Telescope Magazine features the initially released version on the cover, but on page 98 of that issue a ground based CCD image in 'enhanced color' by
Bruce Balick shows this object in a color scheme nearly the 'inverse' of the Hubble image.
NGC 6543 also appears greenish in older color film images. A later version of the Hubble image reprocessed by Mr. Balick better suggests the telescopic colors, and can be seen at his site. Balick's revised HST image appeared on the October 1998 cover of Sky and Telescope.>>
Rings around the Cat's Eye
Posted: Sun May 09, 2010 2:34 pm
by Alex
The APOD image of May 9, 2010, showing the immense halo around the Cat's Eye Nebula reveals a intriguing detail. There are concentric rings or ripples around the Eye. Maybe the rings are merely an artifact of image precessing to enhance the very faint halo. Or do they reveal a natural feature of the nebula that is already known and analyzed? I’ve attached my own enhancement of a part of the APOD image to illustrate the ‘rings around the cat’s eye’. Alex
Re: Rings around the Cat's Eye
Posted: Sun May 09, 2010 2:40 pm
by Chris Peterson
Alex wrote:The APOD image of May 9, 2010, showing the immense halo around the Cat's Eye Nebula reveals a intriguing detail. There are concentric rings or ripples around the Eye. Maybe the rings are merely an artifact of image precessing to enhance the very faint halo. Or do they reveal a natural feature of the nebula that is already known and analyzed? I’ve attached my own enhancement of a part of the APOD image to illustrate the ‘rings around the cat’s eye’. Alex
The scale of the rings suggests that they are real, not processing artifacts. Not sure why there would be any suggestion of gravity waves, though. Gravity waves certainly can't show up in any visible light image. Planetary nebulas are formed by one or more explosions blowing off shells of material, so ripple like structures are not surprising. I don't recall seeing them with the Cat's Eye before, but I have seen similar structure in other planetaries.
Re: Rings around the Cat's Eye
Posted: Sun May 09, 2010 3:08 pm
by Alex
Chris Peterson wrote:Alex wrote:The APOD image of May 9, 2010, showing the immense halo around the Cat's Eye Nebula reveals a intriguing detail. There are concentric rings or ripples around the Eye. Maybe the rings are merely an artifact of image precessing to enhance the very faint halo. Or do they reveal a natural feature of the nebula that is already known and analyzed? I’ve attached my own enhancement of a part of the APOD image to illustrate the ‘rings around the cat’s eye’. Alex
The scale of the rings suggests that they are real, not processing artifacts. Not sure why there would be any suggestion of gravity waves, though. Gravity waves certainly can't show up in any visible light image. Planetary nebulas are formed by one or more explosions blowing off shells of material, so ripple like structures are not surprising. I don't recall seeing them with the Cat's Eye before, but I have seen similar structure in other planetaries.
My assumption is that the rings consist of matter that has been collected and concentrically arranged by standing gravitational waves. Herman Bondi suggested that gravitational waves may be associated with a rotating asymmetric body. He thought diverging and converging waves combine to make the field time-independent thus producing standing waves. Bondi asserted that these standing waves have physical significance and gravitational energy.
Re: Rings around the Cat's Eye
Posted: Sun May 09, 2010 3:40 pm
by Chris Peterson
Alex wrote:My assumption is that the rings consist of matter that has been collected and concentrically arranged by standing gravitational waves.
Not a chance. Gravitational waves at that distance from the central object (which is only stellar mass) would be many, many orders of magnitude too small to concentrate matter. But at that distance you still have significant stellar winds from the central star and the explosion that blew off the material in the first place. Assuming the ripples are real (which I think they probably are) they are just shells of ejected matter from the star.
Re: Rings around the Cat's Eye
Posted: Sun May 09, 2010 3:42 pm
by neufer
Alex wrote:The APOD image of May 9, 2010, showing the immense halo around the Cat's Eye Nebula reveals a intriguing detail. There are concentric rings or ripples around the Eye. Maybe the rings are merely an artifact of image precessing to enhance the very faint halo. Or do they reveal a natural feature of the nebula that is already known and analyzed? I’ve attached my own enhancement of a part of the APOD image to illustrate the ‘rings around the cat’s eye’. Alex
http://www.daviddarling.info/encyclopedia/C/Cats_Eye_Nebula.html wrote:
![Image](http://www.esa.int/images/_catseye_xl.jpg)
Cat's Eye Nebula, 2004 Hubble image
Hubble Space Telescope image taken in 2004
<<Further astonishing detail of the Cat's Eye emerged in 2004 following the release of a new, more detailed Hubble Space Telescope image taken with Advanced Camera for Surveys (ACS). This image reveals a pattern of at least 11 concentric rings, or shells, around the inner portion of the nebula. Each ring is actually the edge of a spherical bubble seen projected onto the sky. Observations suggest the star ejected its mass in a series of pulses at 1,500-year intervals. These convulsions created dust shells, each of which contain as much mass as all of the planets in our Solar System combined.
Until recently, it was thought that such shells around planetary nebulae were rare. However, Romano Corradi (Isaac Newton Group of Telescopes, Spain) and collaborators, in a paper published in the European Journal Astronomy and Astrophysics in April 2004, argued that the formation of these rings is likely to be the rule rather than the exception.
The bull's-eye patterns seen around planetary nebulae came as a surprise to astronomers because they had no expectation of episodes of mass loss at the end of stellar lives that repeat every 1,500 years. Several explanations have been proposed, including cycles of magnetic activity somewhat similar to our own Sun's sunspot cycle, the action of companion stars orbiting around the dying star, and stellar pulsations. Another school of thought is that the material is ejected smoothly from the star, and the rings are created later on due to formation of waves in the outflowing material. Further observations and theoretical studies will be needed to decide between these and other possible explanations.
About 1,000 years ago the pattern of mass loss suddenly changed, and the Cat's Eye Nebula started forming inside the dusty shells. It has been expanding ever since, as discernible in comparing Hubble images taken in 1994, 1997, 2000, and 2002. The puzzle is what caused this dramatic change. Many aspects of the process that leads a star to lose its gaseous envelope are still poorly known, and the study of planetary nebulae is one of the few ways to recover information about these last few thousand years in the life of a Sun-like star. >>
Re: Rings around the Cat's Eye
Posted: Sun May 09, 2010 3:58 pm
by neufer
http://www.daviddarling.info/encyclopedia/C/Cats_Eye_Nebula.html wrote:
<<Further astonishing detail of the Cat's Eye emerged in 2004 following the release of a new, more detailed Hubble Space Telescope image taken with Advanced Camera for Surveys (ACS). This image reveals a pattern of at least 11 concentric rings, or shells, around the inner portion of the nebula. Each ring is actually the edge of a spherical bubble seen projected onto the sky.
Observations suggest the star ejected its mass in a series of pulses at 1,500-year intervals. These convulsions created dust shells, each of which contain as much mass as all of the planets in our Solar System combined...Many aspects of the process that leads a star to lose its gaseous envelope are still poorly known, and the study of planetary nebulae is one of the few ways to recover information about these last few thousand years in the life of a Sun-like star.>>
http://en.wikipedia.org/wiki/Bond_event wrote:
<<
The existence of climatic changes, possibly on a quasi-1,500 year cycle, is well established for the last glacial period from ice cores. Less well established is the continuation of these cycles into the holocene. Gerard C. Bond of the Lamont-Doherty Earth Observatory at Columbia University et al. (1997) argue for a cyclicity close to 1470 ± 500 years in the North Atlantic region, and that their results imply a variation in Holocene climate in this region. In their view, many if not most of the Dansgaard-Oeschger events of the last ice age, conform to a 1,500-year pattern, as do some climate events of later eras, like the Little Ice Age, the 8.2 kiloyear event, and the start of the Younger Dryas.
The North Atlantic ice-rafting events happen to correlate with most weak events of the Asian monsoon over the past 9,000 years, as well as with most aridification events in the Middle East. Also, there is widespread evidence that a ≈1,500 yr climate oscillation caused changes in vegetation communities across all of North America. The hypothesis holds that the 1,500-year cycle displays nonlinear behavior and stochastic resonance; not every instance of the pattern is a significant climate event, though some rise to major prominence in environmental history. Causes and determining factors of the cycle are under study; researchers have focused attention on patterns of tides,
variations in solar output, and "reorganizations of atmospheric circulation.">>
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 4:53 pm
by Mike A
Congratulations on producing such an interesting ( and sometimes beautiful web site).
I think it would be very interesting to state how 'large' the images are in terms of the moon's diameter. In other words if the image of the Halo of the Cats Eye is about the 'size' of the moon it would be fantastic. This extra piece of information will, in my opinion, add interest to the future fantastic pictures that you will feature.
Keep up the good work, you have a fan!
Mike Ashcroft
scrofty@aol.com.uk
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 6:30 pm
by neufer
Mike A wrote:I think it would be very interesting to state how 'large' the images are in terms of the moon's diameter. In other words if the image of the Halo of the Cats Eye is about the 'size' of the moon it would be fantastic. This extra piece of information will, in my opinion, add interest to the future fantastic pictures that you will feature.
Hi Mike, Welcome.
Assuming that you mean apparent angular dimension the core of the Cats Eye is 20″ in diameter
or about the size of Saturn (sans rings) at conjunction; hence, the term "planetary" nebula.
The Halo is an order of magnitude larger than that or ~ 3º in diameter
(~ an order of magnitude smaller than the moon).
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Sun May 09, 2010 9:47 pm
by orin stepanek
The rings around the image kind of remind me of the ripples that a stone leaves when dropped into a lake; radiating out from the center.
![Cool 8-)](./images/smilies/icon_cool.gif)
Julie & Julia
Posted: Sun May 09, 2010 11:15 pm
by neufer
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Mon May 10, 2010 3:17 am
by Astronut
Looks like neufer has fallen into the Fractals. I like the ones that look like ladybugs.
I would like to see a side view of the Hubble's picture of the Cats eye.
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Mon May 10, 2010 3:39 am
by owlice
Both fractals are beautiful, but I especially like the second, which brings to mind Fibonacci numbers and shells such as this:
![Image](http://www.jainmathemagics.com/Editor/assets/webphispiralcolcoseup.jpg)
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Mon Oct 24, 2011 4:11 pm
by laura_abc
wooow, beautiful PICs!
i found more info + pics about it from Hubble
http://blogs.discovermagazine.com/badas ... -eye-halo/
Re: APOD: Halo of the Cats Eye (2010 May 09)
Posted: Mon Oct 24, 2011 4:44 pm
by bystander