Warm dusty rings glow around a weird binary star

By Phil Plait | November 17, 2010 11:15 am

So I’m sitting at home catching up on email, and I get a note from my friend Whitney who does press and outreach for the NASA infrared observatories Spitzer and WISE. There’s a new image from WISE that might be of interest, she claims. OK, I think, clicking the link; WISE images are usually a bit odd — astronomical objects tend to look very different in the far infrared than what I’m used to –but even then, when the image came up on my browser, I was struck by a major dose of holy frakitis:


Wow. And holy frak!* What the heck is that thing?

2001_spacestationYou might be forgiven if your first thought is that it’s the space station from "2001: A Space Odyssey". But in fact it’s something a bit more distant: it’s NGC 1514, the gas and dust surrounding a dying star system about 700 light years away.

I am somewhat familiar with these objects, having studied one for my Master’s degree, and a similar object for my PhD. But planetary nebulae, as they’re called, are so diverse and weird that understanding one, or even several, doesn’t always help in understanding all of them. And this one is seriously freaky. Those rings, lovely as they are, turn out to be quite difficult to explain.

OK, here’s the very brief skinny: when a star like the Sun ages and starts to die, it expands and cools off, becoming a red giant. It blows off a dense, slow wind, like the solar wind it emits now, but much thicker. Over the course of a few hundred thousand years, it can actually shed a lot of its mass. When it does that, it exposes its hot core. The wind speeds up and becomes thinner. This faster wind slams into the older, slower wind, and the collision can sculpt all kinds of weird and wonderful shapes. The hot core of the old star lights up this gas like a neon sign, and you get a planetary nebula (or PN; the plural is planetary nebulae, or PNe).

noao_ngc1514I’m fond of PNe because they’re really quite lovely. Shown here on the left (click to embiggen; you should, it’s a beautiful picture, and note I flipped this and rotated it to match the WISE image) is what NGC 1514 looks like in visible light; note how different it looks than in the WISE far infrared view. In visible light, PNe glow a ghostly green due to oxygen atoms fluorescing. What you see here is the inner shell of material, the hot fast wind from the dying star. The overall shape is roughly round, but there are some features in it like the little loops at the bottom, and apparent cavities in the material or places where dust is blocking our view as well.

But that view changes mightily — though not completely — in the IR. Mind you, WISE doesn’t have the resolution of the ground-based telescope that took the picture above, but even then you can still see some of the same features (I’ve put a close-up of the WISE picture below). The fuzzy green stuff in the WISE image is roughly comparable to what you see in the visible image (the green color is coincidence; the WISE image is false color, since it’s well outside what our eyes can detect).

wise_ngc1514_zoomBut those orange rings! What’s going on there?

The quick answer is: no one knows. Rings like this are really hard to explain, mostly because the physics involved is fiercely complicated. Making things worse is that the star at the center of all this is actually a binary; two stars in orbit around each other. One is the hot, compact core of the dead star, while the other is a cooler giant star also nearing the end of its life. The orbital period of the two is just a few days, meaning they’re really zipping along. This adds angular momentum to the system, making a difficult situation even weirder. Gas is flowing around supersonically, slamming into already-existing walls of gas, and it’s a mess.

But there are a few things we can know. For one, those rings are roughly 0.6 light years in diameter — that’s 6 trillion kilometers (3.6 trillion miles). That number is not precise because the distance is not well known; the usual distance determination methods used by astronomers aren’t reliable for PNe, but 700 light years is a decent estimate.

The rings are very close together, separated by roughly 0.15 light years (1.5 trillion km, 900 billion miles). We see rings in quite a few PNe (NGC 3132 is another good example, as is the weird structure around Supernova 1987A), but they’re usually separated by about the same distance as their diameters. Obviously, something odd is going on here. If we assume the rings are actually circular loops seen at an angle (that’s a pretty solid assumption) then we can measure that the axis of the nebula is tilted to our line-of-sight by about 60° (in other words, were it tipped another 30° we’d see it exactly along its equator, and the rings would look like two parallel lines).

tunacanIn fact, weirdly, that space station picture above is a pretty close model of what this nebula looks like in the sky! See how, from our point of view, the loops overlap in the space station? The same thing is happening in NGC 1514. It’s tilted enough that the rings are superposed on one another. And the ring to the left is closer to us than the one on the right — I rotated the space station image to match the geometry. Another way to think of it is that the nebula is tipped so that we’re seeing the bottom of it on the left, like the tuna can in the picture. I know, I spare no expense in explaining the science here!

The nebula rings aren’t really orange; again it’s a false color image. But what that color indicates is their temperature of about 160K, which is cold in human terms (about -110° C or -170° F) but astronomers would call that warm for a deep space object. What we’re seeing is almost certainly dust ejected by the star. But why rings?

The astronomer who found this object in the WISE data, Michael Ressler, has published a paper about it, but even after all the analysis done by him and his team, the reason the rings exist isn’t clear. Is it simply that the central star expelled a big cloud of dust, and we’re seeing it hit the gas from the old red giant? Or is the exposed core of the star sending out beams of material and energy that are hitting that gas, lighting them up? Certainly the fact that there are actually two stars in a tight orbit has something to do with this, but just what exactly?

No one knows. I chatted with Dr. Ressler about this last night, and we both expressed a need for high-resolution, deeper observations using Hubble (and maybe JWST, the infrared observatory that will succeed Hubble in a few years). And by "expressed a need", I mean we both kinda sighed wistfully over having data like that. Planetary nebulae are totally cool, and amazingly beautiful, and wonderfully mysterious. A lot of the basic physics about them is well-understood, but when you dive into the details things get hard fast.

PNe are telling us that in many ways our understanding of the Universe is pretty good, but the closer you look, the more complicated things get. That’s not terribly surprising, but it once again affirms one of the most basic realities of science: the more you understand, the more there is to understand. In a long list of things I love about science, that one’s near the top.

Image credits: IR image: WISE ; Optical: Adam Block/NOAO/AURA/NSF

* Told ya.

Related posts:

The Helix’s dusty heart
The first spectacular views of the sky from WISE
20 years ago today

CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post

Comments (61)

  1. Thanks for the tuna can of scienceTM! It helps picture things. So, is this nebula that chicken of the sky?

  2. Wow, that’s beautiful.

    It’s so bizarre that exploding stars can create rings like that!

  3. Alan in Upstate NY

    I think it’s a giant cat toy.

  4. Keith Bowden

    If you run across a box-shaped one, that’s a TARDIS in flight…

  5. Cindy


    Planetary Nebulae are not formed from exploding stars (supernovae). It’s a lot longer and more gentle process.

    Cool picture, Phil!

  6. I think the explanation is blatantly obvious: double Ringworld system.

  7. Steve

    The Puppeteers might know. Clearly Ringworlds built by the civilization of the dying binary 😉 😉

  8. khan

    I recall a SNL routine: “What the Hell is that?”

  9. Spencer

    Couldn’t the second star be heating the gas? I just spent the last 10 minutes thinking hard and that’s all this amateur astronomer can think of.

  10. Your last paragraph reminded me of why I love psychology–we may know a lot about the brain, but there’s so much more we can’t explain yet.

    Astronomy will always hold a place in my heart and I love looking at pictures of things in deep space trying to understand the science behind them. Thanks for the tuna can view and an explanation for us laymen/amateur astronomers. *grin*

  11. Donnie B.

    Two victories for the rebellion. Scratch a pair of Death Stars in one system!

  12. Nicholas Suntzeff

    the rings are like the outer rings in 87A

  13. “I’ll tell you what that is. It’s interesting fauna!”
    I know it’s nebulae, but I’ll prolly just continue with my abbreviation…
    Gotta love me some PNs!
    And fake HTML tags too!

  14. mike burkhart

    You know it dose kind of look like the space station in 2001.

  15. Nemesis

    It is most certainly the watchful eye of Sauron.

  16. Joseph G (AG in SC)

    I’ve always wondered: How difficult IS it for an astronomer to get time on the Hubble (or to ask the Hubble mission people to point it at an object, I’m not sure exactly how it’s administrated)?

    I’m sure pretty much every astronomer who’s looking for visible-light data would love to have use of the Hubble – how is it decided who gets to go first? Is there a years-long queue that you need to wait in? Do you write a research proposal to the Hubble team, and they pick out what gets imaged next based on their opinion of the proposals?

  17. Joseph G (AG in SC)

    Regarding the Ringworld “hypothesis” – if those are what we’re seeing, you’d expect the portions of the rings that we see on the far side of the system (facing the central stars) to look much brighter in infrared (they’d be the temperature of a habitable planet, after all).
    One would wonder why there are two of them, but then, as has been pointed out numerous times, ringworlds aren’t stable anyway, so you’d need to be able to magically move them around, so hey, why the hell not have two? 😛

  18. JMW

    The Gandalf Nebula.

    It is blowing smoke rings, after all.

  19. QuietDesperation

    You might be forgiven if your first thought is that it’s the space station from “2001: A Space Odyssey”

    Mmmmmm, no. I would not forgive an educated adult for looking at an interstellar photo and thinking it was a space station from a work of fiction.

    I recall a SNL routine: “What the Hell is that?”

    Whoa. Flashback.

    “Don’t put your lips on it!”

    I think the explanation is blatantly obvious: double Ringworld system.

    Yes. Double the rings! Double the instability! Yay!

  20. Jesse

    I really love reading these articles by Phil, they make me think that maybe I can do something like this some day….

  21. Tavo

    Hmmm… the more I look at it, the more it looks just like two bubbles together, not rings, so we only see the edges of the two bubbles… like certain pictures of supernovae, which show a “ring” around the exploding star, but instead it’s just the edge of the expanding bubble…
    Then again, I’m no scientist, I’m just curious :)

  22. Maybe I was consider very, very slow explosions to still be explosions.

    . . .


  23. Sean

    Isn’t that what Green Lantern’s planet Oa looks like in the comics now? or am I just stuck after seeing the new trailer for the upcoming movie?

  24. Jeff

    ” I was struck by a major dose of holy frakitis:”

    this is a good exclamation, because this image is nothing short of AWESOME. it is becoming unbelievable how good these images are getting, and they make a qualitative step from the old fashioned black and white photos: these allow a good scientist like Phil to hypothesize as to what the processes that are going on . Imagine what this thing would look like if you really got within like a few AU of it?

  25. Jeff

    “A lot of the basic physics about them is well-understood, but when you dive into the details things get hard fast.”

    I can attest to this being a physics major. Basic physics is pretty easy, but start reading a book on advanced electrodynamics like Jackson, and you’ll see that things really do get complex quick.

  26. Yojimbo

    Whaddaya mean instabilities? The Ringworld Engineers put in stabilizers…

  27. DigitalAxis

    @16. Joseph G (AG in SC):
    Getting time on the Hubble Space Telescope is based on research proposals, like nearly all other observatories. Your proposal ends up being evaluated by astronomers (not necessarily employed by the observatory, though they usually have used the telescope before) based on
    merit of the observations (ie, how important/useful are they?),
    how feasible they are (can the Hubble ACTUALLY get data that will answer the question you claim to be asking?),
    the amount of time you’re asking for, prior work in the field (do you and your team have a track record showing you’ll actually be able to interpret the results you need from the Hubble data?),
    and why you specifically need to use the Hubble Space Telescope to get what you want, as opposed to another telescope.
    (also, what do the other proposals look like?)

    That last one is fairly important nowadays seeing as the Hubble Space Telescope gets ten times as many requests (by total observing time) as it can actually carry out. (Although, as some colleagues have noted, some ground-based telescopes are actually MORE oversubscribed)…
    The only major exception to stuff like this is certain institutions that build or host a telescope get time set aside just for their use, like the Keck Telescopes on Mauna Kea: Time is specially set aside for proposals from the University of California system and Caltech (who built them) and the University of Hawai’i (who hosts them).

  28. aelfheld

    Somewhere there is a large glowing cat, wishing it could master the cosmic can-opener.

  29. Lars

    It’s astronomy’s double-rainbow! What does it mean?

  30. Heather

    That is EFFING awesome. This rivals some of the early hubble pictures I saw back when I was working at the UofA mirror lab and seeing all kinds of stuff I probably wasn’t ACTUALLY supposed to see.

  31. CB

    Mmmmmm, no. I would not forgive an educated adult for looking at an interstellar photo and thinking it was a space station from a work of fiction.

    But I will forgive you, a presumably educated adult, for not taking the comment in the metaphorical sense it was clearly intended. :)

  32. Skeptic Tim

    Phil, when you pine…

    “I chatted with Dr. Ressler about this last night, and we both expressed a need for high-resolution, deeper observations using Hubble (and maybe JWST, the infrared observatory that will succeed Hubble in a few years). And by “expressed a need”, I mean we both kinda sighed wistfully over having data like that.”

    So what would it take to get Hershel pointed at that object? Surely that could be done more quickly then waiting for JWST!

  33. chris j.

    NGC 1514 is the PN of a dead star that has been kissed by a close binary. you know, the tuna-can PN … the “starkist” nebula.

    thanks, i’m here all week!

  34. Gerry

    It’s just an on-location test for George Lucas by Industrial Light and Magic.
    He has altered the deal, pray he doesn’t alter it further….

  35. baric

    ” so hey, why the hell not have two?”

    As we all know from watching Contact, this is clear evidence that the rings are a government project.

  36. Dan

    hooo! double ring all the way!….what does it mean?? it’s do beautiful!!!

  37. Brian Too

    No Phil, you’ve solved it. Case closed, it’s the Tuna Nebula*.

    Nothing more to see here, move along!

    * Technically, the Tuna Can Nebula. But that’s for the advanced class only.

  38. Who is Good Will?

    So what would it look like if astronomers found a ringworld or a Dyson Sphere? Would it be warm enough to be detected? Would it be would it be detectable by radio telescope? What’s acceptable criteria for saying “ah ha — what we’re observing is not naturally occurring”?

  39. Pete Jackson

    Beautiful picture and article, Phil

  40. Joseph

    @ QuietDesperation My first thought was also Ring Worlds of some kind. Perhaps two Dyson Rings established to harness the energy as each star dies.

    Yes yes I know there are more appropriate explanations as per Occam but a dual Dyson Ring set up for energy purposes is much cooler sounding.

  41. Messier Tidy Upper

    @39. Pete Jackson : I second that. :-)

    Magnificent image, cosmically wonderful Planetary Nebulae & excellent write-up. I love it. 😀

    “The Space Odyssey Space Sation” Nebula has to be the nickname for NGC 1514 surely hasn’t it? 😉

  42. Rick

    @38. Who is Good Will?:
    I would think they would be able to notice using visible light telescopes a series of blocked out portions of the visibility of the stars that would not correspond to planetary orbits.

    Could it be that they’re not actually rings but just appear to be that way because of low picture quality? It kinda looks like one of those field lines you see when you put iron filings near a bar magnet.
    Could this be a similar concept with gravitational fields?
    And if so, perhaps it’s the friction that’s causing them to heat up?

    Just my armchair ramblings.

  43. Messier Tidy Upper

    @24. Jeff :

    Imagine what this thing would look like if you really got within like a few AU of it?

    I’m imagining what it would look like from the *inside* maybe a moon or planet orbiting the binary and what their bnightskies may be like.

    But then I remember its in infra-red so it may not look like anything special – unless they have an IR camera. Which remidns me of this :


    Loking at a similar IR-only visible outermost ring of saturn starring Amy Okuda.


    “So we just discovered the largest ring ever around Saturn but it’s invisible?”

    “Basically, yes.” 😉

  44. Mike Ressler (yes, that one)

    Hi everyone – I enjoyed reading your comments, and am glad you are finding NGC 1514 as beautiful as I did. Between the “Tuna Can Nebula” and the “Space Odyssey Space Station Nebula”, I think we have a couple of winners.

    Just a comment: believe me, Hubble and Herschel imaging have been discussed, but it is awfully difficult to get time to look at a single, pretty object. I have not used either telescope and this is also my first foray into planetary nebula science (I usually do star formation), so my “standing” or “track record” as mentioned above is also about zero. Director’s discretionary time or Hubble Heritage time is likely to be the only avenue, and getting that is also exceedingly difficult. But, one never knows …

    I’d be happy if a few amateurs with access to large scopes would take a good shot at it. The brightness of the central star makes it a challenge, but perhaps narrow band imaging both on some bright lines and, maybe even better, on the neighboring continuum might pull something out. Cheers!

  45. Jenn

    Wow. That’s all I can say.

  46. Paddy

    Maybe someone blew up a ringworld 😉

  47. @26 – “Whaddaya mean instabilities? The Ringworld Engineers put in stabilizers…”

    Yeah, and then they got… uh… stolen recycled… by their kids, for exploration and trade.

    More seriously – I’m surprised nobody (including you Phil) has mentioned shockwaves.

  48. JustCurious

    “Gas is flowing around supersonically, slamming into already-existing walls of gas, and it’s a mess. ”

    How does “supersonically” relate to this environment? To a layman, it doesn’t seem particularly fast in terms of cosmic phenomena. What am I missing?

  49. George Reagan

    I believe that you described the orange rings correctly. They are like the sonic shock waves we experience here on the ground. The faster exploding gasses are meeting the slower expanding gasses. Two rings exist due to the two stars similar actions. I experienced like images while studying with Prof. Gott at Texas Tech Univ. back in the 1970’s. George Reagan, Fort Worth, Texas.

  50. Trebuchet

    Nos. 48 and 49, you may be sort of answering each other’s questions.

  51. TomC

    Ref Phil’s comment “Gas is flowing around supersonically, slamming into already-existing walls of gas.” OK – what is the speed of sound in an interstellar gas at -110C?

    Hmm, should this replace my Age of the Universe pix as a desktop background?

  52. @50 -> @49 – “supersonically”


    Um… it’s a vacuum… superSONICally…

    +++ DOES NOT COMPUTE +++
    +++ REDO FROM START +++

    A shockwave doesn’t have to be caused by sound – but pressure – and in a vacuum, where does the pressure come from? By the bits of stuff that are spewed out by whatever it is that ‘explodes’ or whatever it does – so in this instance, superSONIC could instead be purely a measure of velocity.

  53. noen

    It is obviously the universe’s reboot button. Push it and the simulation starts all over again.

  54. Jon Hanford

    Hey, the paper on NGC 1514 Phil mentions in his piece has been posted: http://arxiv.org/PS_cache/arxiv/pdf/1011/1011.3877v1.pdf

    I would encourage curious lay readers to check it out, too, as it includes many cool color and B&W images of NGC 1514 that Phil couldn’t fit in his article!

    Off topic but kool: A paper has been posted (over at arXiv dontcha know) that presents a 3-D multiwavelength look at the Cassiopeia A Supernova Remnant. But wait! There’s more! Also included is a short video of their model and a tres cool 3-D PDF file that lets you view their model at any angle you wish. Maybe Phil will do a write-up of this paper sometime. Anyway, you can check out “The Three-Dimensional Structure of Cassiopeia A” here: http://arxiv.org/abs/1011.3858

    (video & 3-D PDF links at bottom of page)

  55. Captn Tommy

    I am an engineer, and as such looking at this beautiful picture of NGC 1514 I can only solve your double ring mystery as a gas flow exercise.

    1. Take a spinning ball (representing the star). Now stars, even our sun, are blowing off particles in the solar wind (SW) these travel outward into the heliopause and stop? Thus forming a tenuous ring of gas. Now physics would indicate that the particles leaving the equator of the star would be traveling faster than rest of the SW particles so these would create a thicker area of the ring and the Star System Equator.

    2. Our ball has a series of holes around the spin equator which in a vacuum eject cigarette smoke which (at least for this explanation) disperse in a ring, the dispersion angle depending on mass and velocity.

    3. Now at a point to represent the Death Throw mass ejection, an impulse of very high pressure air is “blasted” from our Ball. This represents the high velocity gas/particles of this ejectio in relation to the SW. This blast tears into the center of our existing low velocity ring, the velocity of this blast would be such even in our model that dispersion angle would be much less than the slow SW ring. Boom, the blast wave tears through the center of the center of the ring wall. (This ;oks like in the model as the thick wave front created by the slowing of the dispersed gas/smoke (picture the wave front of a dust/sand storm)) the high velocity impulse blows through the center of this wall.

    4. The resulting affect is the turbulent reaction you would see of an aircraft bursting thru a cloud or a slow speed camera shot of a bullet passing thru a screen of water or even better the creation of a smoke ring. But in the star NGC 1514 that impulse is created on the entire circumference of the previous SW ring, Thus two smoke rings, per sea, are created. These move away from each other at a velocity related to the velocity of the impact force. Unfortunately it is easier to show this in a drawing that to describe it in writing. Impact at relativistic speeds would create the heat signature illuminating the rings as in the photo.

    5. Using math and good guess work the velocity and separation distance of the rings (I.5 Lightyears) could be worked backward to find the time of the impact.

    “Simple physics” and nature observations of earthbound gas/fluid interaction modeling sometimes lead to the simplest answers. If anybody tries this experiment please acknowledge the source. Engineers have egos too 

    Think About It.
    Captn Tommy

  56. Interskeptor

    …I’m with Tavo here.
    Also not an expert, I am not convinced that these are actually rings. They ‘d be irregular, showing irregularities “exactly” on those points where they “cross” the other “ring” in the “background”.
    Squashed bubbles, yes. Thats my guess. … until you provide me with a 3D-view of it… :-)

    Could that ring-thing be pareidolia? :-)

    I’m waiting for more evidence…

  57. Andrew

    The rings remind me of the light echoes observed with SN1987a. Could this be a similar phenomenon?

  58. mharratsc

    Wow, people. Seriously?? Hourglass/dumbbell shapes are seen throughout the universe, both at the stellar and galactic levels. This isn’t the first- Hourglass Nebula, Ant Nebula, Bowtie Nebula, etc.

    Oh yeah, for all you science wizzes- these forms are seen daily in plasma labs on Earth. It’s called a Bennett or ‘Z’-pinch. No new physics required.

    Occam’s Razor and all that…

  59. brant

    Itsa plasma. It refuses to realize how elegant mathematical equations are.

    It also refuses to follow “gas” laws because it is a plasma.

    MHD is also of no use in this situation. I would probably model this with PIC.

    Nothing “fiercely complicated” about it. It follows the laws of plasma in a laboratory.

  60. Mike Ressler (yes, that one)

    @59: mharratsc – We never claimed this is the only hourglass. We discuss the Hourglass and Southern Crab nebulae in our paper. However, NGC 1514 is one of the few (if not the only one) that shows the ringed stucture only in the infrared. The others you mention show the bells and whistles in optical wavelength line emission, whereas NGC 1514 does not. The formation mechanisms are likely to be very similar, however. (Maybe for SN1987a as well; no one really understands how those rings formed either, even after 23 years.)

    @59, 60: mharratsc, brant – Except that the rings are not plasma. The spectra of the rings are consistent with thermal emission from dust with a range of temperatures of order 160 K. Plasmas and magnetic fields are likely to play a role near the white dwarf where a jet might be accelerated that impacts the surrounding dust and heats it up, but the ring material that WISE sees is not simply a focused plasma.

    “Fiercely complicated” because no two PNe are alike, so you can’t just turn your model crank and expect a given planetary to pop out. While we do understand many of the basic principles, there are many initial conditions that one has to take into account (single star vs binary star, binary orbital parameters, local ISM conditions, metalicity, wind speeds, etc.), all of which can change the general appearance of a PN dramatically. Even then, the closer you look at a given object, the more there is to see: the fine structure in the interior of things like the Helix Nebula is astounding, and no model will (yet) replicate that in detail.

    This is why the rings in NGC 1514 are “unexpected”: no model based on data available before WISE would have predicted them. But this is also why we build and fly things like WISE – you never really know what you are going to see before you try.


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