APOD: Halo of the Cat's Eye (2014 Jun 01)

[APOD Robot]

Halo of the Cat's 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.

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[MarkBour]

That is a gorgeous image!
How has an estimate of the age of the outer filaments been made?

[Boomer12k]

Maybe the Russians could put my 10" Meade up in space.....then I could get a nice clear picture of it....I get a small fuzzy patch...color...but a small fuzzy patch....

This is an awesome pic of it....

I hope someone in a far solar system is able to see the Planetary Nebula left by our Sun, SOL.....maybe around 5 billion more years....

:---[===] *

[neufer]

How has an estimate of the age of the outer filaments been made?

Basically he same way the age of the universe (from the Big Bang) is determined:

• 1) A Doppler measurement of the current expansion rate in combination
  
  2) with a simple physical model of the average expansion rate over time.

Run the model in reverse back to the start of the "explosion."

[BDanielMayfield]

The strangest part of this outer halo is near the right edge. There's a piece that resembles the cone nebula or a comet, but its orientation is odd, like it's moving at nearly a right angle to the stellar wind. How might this be explained?

[neufer]

The strangest part of this outer halo is near the right edge. There's a piece that resembles the cone nebula or a comet, but its orientation is odd, like it's moving at nearly a right angle to the stellar wind. How might this be explained?

Not all that different from the "wing tips" of the "very central region."

Perhaps it used to be one of the "wing tips" of the "very central region."

[BDanielMayfield]

Perhaps it used to be one of the "wing tips" of the "very central region."

But this outer feature is assimmetrical with respect to the central star. I could go along with your suggestion if there was something like it on the left, but there isn't.

Could this comet like object be caused by something in orbit of the central star interacting with its ejecta?

[Chris Peterson]

The strangest part of this outer halo is near the right edge. There's a piece that resembles the cone nebula or a comet, but its orientation is odd, like it's moving at nearly a right angle to the stellar wind. How might this be explained?

I'd say it's the pattern recognition system of your brain coming to a false conclusion. You're not looking at something moving perpendicular to the radial flow, you're looking at a shock front moving outwards with everything else. Because it's denser at one end than the other, your brain is screaming "comet". Of course, even comets are seldom actually moving in the direction our minds try to convince us they are.

[geckzilla]

"wing tips"

https://en.wikipedia.org/wiki/Fast_Low- ... ion_Region
A somewhat neglected little Wiki article...

[BDanielMayfield]

The strangest part of this outer halo is near the right edge. There's a piece that resembles the cone nebula or a comet, but its orientation is odd, like it's moving at nearly a right angle to the stellar wind. How might this be explained?

I'd say it's the pattern recognition system of your brain coming to a false conclusion. You're not looking at something moving perpendicular to the radial flow, you're looking at a shock front moving outwards with everything else. Because it's denser at one end than the other, your brain is screaming "comet". Of course, even comets are seldom actually moving in the direction our minds try to convince us they are.

I haven't come to any conclusion, false or otherwise, and I realize that there is no way this could be a comet for several reasons. Actually, what this "object" reminds me of most is a particle leaving a vapor trail in a cloud chamber, so I would respectfully ask, is it possible that there could be an orbiting or just passing object like a gas giant to red dwarf star mass inside the dense end that is leaving a trail-like wake in the ejecta it is passing through?

Bruce

[Chris Peterson]

I haven't come to any conclusion, false or otherwise, and I realize that there is no way this could be a comet for several reasons.

I wasn't suggesting that you had come to a conclusion, and most certainly not that you thought it was a comet. I was suggesting that your brain's pattern recognition system was leading the conscious part of yourself towards a false conclusion. Our brains do that all the time. It is natural to see this as something moving perpendicular to the radial flow. That's what our visual system tries to force on us.

Actually, what this "object" reminds me of most is a particle leaving a vapor trail in a cloud chamber, so I would respectfully ask, is it possible that there could be an orbiting or just passing object like a gas giant to red dwarf star mass inside the dense end that is leaving a trail-like wake in the ejecta it is passing through?

No chance at all. It's just a boundary of slightly denser gas, moving outwards like everything else here.

[LocalColor]

Wonderful photo of one of my favorite nebulas. Learn something new every time I come to APOD.
Thanks!

[meadowlark7]

As the sun revolves around the Milky Way in a span of several hundred million years, will it likely pass through dust clouds or star forming regions and perhaps pick up mass that will defer its ultimate demise?

[Chris Peterson]

As the sun revolves around the Milky Way in a span of several hundred million years, will it likely pass through dust clouds or star forming regions and perhaps pick up mass that will defer its ultimate demise?

The Solar System will certainly pass through dust, and possibly some active star forming regions. Neither will have any effect on it. The densest gas and dust regions are still hard vacuums, and even the paltry wind from our stable little star will blow away anything long before it could be captured and add any mass.

[neufer]

As the sun revolves around the Milky Way in a span of several hundred million years, will it likely pass through dust clouds or star forming regions and perhaps pick up mass that will defer its ultimate demise?

The Solar System will certainly pass through dust, and possibly some active star forming regions. Neither will have any effect on it. The densest gas and dust regions are still hard vacuums, and even the paltry wind from our stable little star will blow away anything long before it could be captured and add any mass.

[b][color=#0000FF][size=150]The ribbon of ENA emissions seen in the IBEX map[/size][/color][/b]

---

• Except, perhaps, for some ENAMAss:

<<IBEX is collecting Energetic neutral atom (ENA) emissions that are traveling through the solar system to Earth that cannot be measured by conventional telescopes. These ENAs are created on the boundary of our Solar System by the interactions between solar wind particles and interstellar medium particles.

On the average IBEX-Hi detects about 500 particles a day, and IBEX-Low, less than 100. By 2012, over 100 scientific papers related to IBEX were published, described by the PI as "an incredible scientific harvest".>>

[BDanielMayfield]

One other thing though. I wonder what might account for the brightest part of the halo on the right side?

[geckzilla]

One other thing though. I wonder what might account for the brightest part of the halo on the right side?

It's a mess blowing off your outer layers, especially if you've got another star orbiting nearby. You should try to think of its three dimensional structure. It's too easy to forget that we are viewing a spherical structure when they look so much like they are flat disks and we just happen to view them face on.

[BDanielMayfield]

One other thing though. I wonder what might account for the brightest part of the halo on the right side?

It's a mess blowing off your outer layers, especially if you've got another star orbiting nearby. You should try to think of its three dimensional structure. It's too easy to forget that we are viewing a spherical structure when they look so much like they are flat disks and we just happen to view them face on.

I was thinking three and even four dimensionally, and I do think it has another star nearby. I was thinking that there might even be a star somewhere close to or embedded inside the brighter part of the halo on the right side, lighting it up. Something has to be making that part of the halo brighter. What do you think?

[Chris Peterson]

I was thinking three and even four dimensionally, and I do think it has another star nearby. I was thinking that there might even be a star somewhere close to or embedded inside the brighter part of the halo on the right side, lighting it up. Something has to be making that part of the halo brighter. What do you think?

Yes, but keep in mind that the halo is barely brighter than the sky background- orders of magnitude dimmer than the central planetary nebula (composited from an HST image). The halo is made from narrowband images, which dramatically reduce the intensity of any stars in the field. Bottom line: it's really difficult to make any solid assessments about how bright anything is here. But most likely, virtually all the light of the halo is emitted, not reflected. The bright area to the right is larger than other bright spots, but not brighter. I think it's probably just another region that's shocked, or is just a little denser and therefore brighter from the stimulation of the central star.

[BDanielMayfield]

I was thinking three and even four dimensionally, and I do think it has another star nearby. I was thinking that there might even be a star somewhere close to or embedded inside the brighter part of the halo on the right side, lighting it up. Something has to be making that part of the halo brighter. What do you think?

Yes, but keep in mind that the halo is barely brighter than the sky background- orders of magnitude dimmer than the central planetary nebula (composited from an HST image). The halo is made from narrowband images, which dramatically reduce the intensity of any stars in the field. Bottom line: it's really difficult to make any solid assessments about how bright anything is here. But most likely, virtually all the light of the halo is emitted, not reflected. The bright area to the right is larger than other bright spots, but not brighter. I think it's probably just another region that's shocked, or is just a little denser and therefore brighter from the stimulation of the central star.

Thanks, I can certainly accept that logic.

[geckzilla]

Yeah, I don't think that the bright star has anything to do with what is apparently a coincidentally denser area. The star had a bad day that day.

[southern cross]

Many thanks for this image. I totally did not know about the halo of the Cat's Eye.

[neufer]

Perhaps it used to be one of the "wing tips" of the "very central region."

But this outer feature is asymmetrical with respect to the central star. I could go along with your suggestion if there was something like it on the left, but there isn't.

Could this comet like object be caused by something in orbit of the central star interacting with its ejecta?

<<The Cat's Eye Nebula is structurally a very complex nebula, and the mechanism or mechanisms that have given rise to its complicated morphology are not well understood. It is suspected that the central star of the nebula may be a binary star. The existence of an accretion disk caused by mass transfer between the two components of the system may give rise to polar jets, which would interact with previously ejected material. Over time, the direction of the polar jets would vary due to precession.>>

[Ron-Astro Pharmacist]

I think I've asked this before but should the original star had gas giant planets within close proximity (or far) from the star sloughing off matter – could their remnants be noticeable or dectected amongst the star material being ejected?

[Chris Peterson]

I think I've asked this before but should the original star had gas giant planets within close proximity (or far) from the star sloughing off matter – could their remnants be noticeable or dectected amongst the star material being ejected?

The creation of a planetary nebula is actually pretty gentle. Any planets in the system should be largely unaffected, although their orbits will necessarily change somewhat because of the lost central mass. But it's reasonable to assume that most planets would still be in orbit. They wouldn't have a visible effect on the nebula, but could potentially be detected using one of the techniques used for doing so (transits, Doppler, direct imaging, etc).