Cosmic sprinklers explained: Odd pair of aging stars sculpt spectacular shape of planetary nebula

Nov 08, 2012
This new ESO Very Large Telescope image shows the planetary nebula Fleming 1 in the constellation of Centaurus (The Centaur). This striking object is a glowing cloud of gas around a dying star. New observations have shown that it is likely that a very rare pair of white dwarf stars lies at the heart of this object. Their orbital motions can fully explain the remarkably symmetric structures of the jets in the surrounding gas clouds in this and similar objects. Credit: ESO/H. Boffin

(Phys.org)—Astronomers using ESO's Very Large Telescope have discovered a pair of stars orbiting each other at the centre of one of the most remarkable examples of a planetary nebula. The new result confirms a long-debated theory about what controls the spectacular and symmetric appearance of the material flung out into space. The results are published in the 9 November 2012 issue of the journal Science.

Planetary nebulae are glowing shells of gas around —Sun-like stars in the final stages of their lives. Fleming 1 is a beautiful example that has strikingly symmetric jets that weave into knotty, curved patterns. It is located in the southern constellation of Centaurus (The Centaur) and was discovered just over a century ago by Williamina Fleming, a former maid who was hired by Harvard College Observatory after showing an aptitude for astronomy.

Astronomers have long debated how these symmetric jets could be created, but no consensus has been reached. Now, a research team led by Henri Boffin (ESO, Chile) has combined new Very Large Telescope (VLT) observations of Fleming 1 with existing computer modelling to explain in detail for the first time how these bizarre shapes came about.

The team used ESO's VLT to study the light coming from the . They found that Fleming 1 is likely to have not one but two white dwarfs at its centre, circling each other every 1.2 days. Although binary stars have been found at the hearts of planetary nebulae before, systems with two white dwarfs orbiting each other are very rare.

"The origin of the beautiful and intricate shapes of Fleming 1 and similar objects has been controversial for many decades," says Henri Boffin. "Astronomers have suggested a before, but it was always thought that in this case the pair would be well separated, with an of tens of years or longer. Thanks to our models and observations, which let us examine this unusual system in great detail and peer right into the heart of the nebula, we found the pair to be several thousand times closer."

When a star with a mass up to eight times that of the Sun approaches the end of its life, it blows off its outer shells and begins to lose mass. This allows the hot, inner core of the star to radiate strongly, causing this outward-moving cocoon of gas to glow brightly as a .

While stars are spherical, many of these planetary nebulae are strikingly complex, with knots, filaments, and intense jets of material forming intricate patterns. Some of the most spectacular nebulae—including Fleming 1—present point-symmetric structures. For this planetary nebula it means that the material appears to shoot from both poles of the central region in S-shaped flows. This new study shows that these patterns for Fleming 1 are the result of the close interaction between a pair of stars—the surprising swansong of a stellar couple.

"This is the most comprehensive case yet of a binary central star for which simulations have correctly predicted how it shaped the surrounding nebula—and in a truly spectacular fashion," explains co-author Brent Miszalski, from SAAO and SALT (South Africa).

The pair of stars in the middle of this nebula is vital to explain its observed structure. As the stars aged, they expanded, and for part of this time, one acted as a stellar vampire, sucking material from its companion. This material then flowed in towards the vampire, encircling it with a disc known as an accretion disc. As the two stars orbited one another, they both interacted with this disc and caused it to behave like a wobbling spinning top—a type of motion called precession. This movement affects the behaviour of any material that has been pushed outwards from the poles of the system, such as outflowing jets. This study now confirms that precessing accretion discs within binary systems cause the stunningly symmetric patterns around planetary nebulae like Fleming 1.

The deep images from the VLT have also led to the discovery of a knotted ring of material within the inner nebula. Such a ring of material is also known to exist in other families of binary systems, and appears to be a telltale signature of the presence of a stellar couple.

"Our results bring further confirmation of the role played by interaction between pairs of stars to shape, and perhaps even form, planetary nebulae," concludes Boffin.

Explore further: 'Eye of Sauron': Using supermassive black holes to measure cosmic distances

More information: "An Interacting Binary System Powers Precessing Outflows of an Evolved Star," by H.M.J. Boffin, Science, 2012. www.sciencemag.org/content/338/6108/773.abstract

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User comments : 14

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LagomorphZero
not rated yet Nov 08, 2012
Paired white dwarfs are a possible cause of type-Ia supernovas, and with a 1.2 day orbit, we should keep an eye or two on this for the future!

http://phys.org/n...-ia.html
cantdrive85
1 / 5 (11) Nov 08, 2012
"While stars are spherical, many of these planetary nebulae are strikingly complex, with knots, filaments, and intense jets of material forming intricate patterns. Some of the most spectacular nebulae—including Fleming 1—present point-symmetric structures."

These are ALL descriptions of the characteristics of plasma used by plasma physicists.

"Astronomers have long debated how these symmetric jets could be created, but no consensus has been reached."

"Students using astrophysical textbooks remain essentially ignorant of even the existence of plasma concepts, despite the fact that some of them have been known for half a century. The conclusion is that astrophysics is too important to be left in the hands of astrophysicists who have gotten their main knowledge from these textbooks. Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory." Hannes Alfven
HannesAlfven
1 / 5 (10) Nov 08, 2012
Joseph Novak based his entire theory of education on the observation that students exhibit surprising difficulty correcting misconceptions. He invented the concept map in order to help people to correct misconceptions. The CMapTools (concept mapping) software was funded, in part, by the NSA, NASA and the Department of Navy -- all of which use the software. From there, he retired from Cornell University in order to move on to a consultant position at Proctor & Gamble, the world's largest consumer goods company.

What all of these extraordinary organizations have discovered is that misconceptions are an incredible impediment to critical thinking. Perhaps the best example of what happens when people ignore the role of misconceptions to our systems of belief is happening today, at this very moment, in the astrophysical discipline. We are told that the world must bend to them, be nice to them, in hopes they will come around.

The world can and will leave you behind, astrophysics.
HannesAlfven
1 / 5 (10) Nov 08, 2012
None of us should pain themselves too much in trying to understand why it is that this discipline refuses to question its assertions, and insists upon building an enormously speculative structure upon this incredibly shaky foundation. The fact is that we all intuitively know that there is something wrong with our science education. But, who among us takes the next logical step, of wondering what are the ramifications of this antiquated system of science education for scientific theory?

We have focused far too much upon problem solving in the physics PhD program, to the detriment of concepts. The end result is that we have predictably flooded the astrophysical discipline with quantifiers, who lack the skills necessary to question the one model that they know. You cannot question your worldview in science through problem sets. The only way to do that is through a training program which emphasizes concepts, concept mapping and multi-framework argumentation.
barakn
5 / 5 (5) Nov 09, 2012
Ooo, my shoelaces are shaped like filaments, they must be shaped by electricity.
A2G
5 / 5 (2) Nov 09, 2012
"Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory." Hannes Alfven

That kind of leaves the EUT crowd out then as they have never done even one lab experiment. :0
cantdrive85
1 / 5 (3) Nov 09, 2012
And the ad hominem and straw man arguments begin from the pseudo-skeptics.
barak, if your shoelaces have magnetic fields and emit EM radiation as the nebula is observed to have, you may be correct.
cantdrive85
1 / 5 (4) Nov 09, 2012
A2G, there is a great deal of information about plasma and it's characteristics, research has been going on for over a hundred years now (not only in your imaginary lab). There are a couple people out there who actually use information that other people produce to formulate their hypotheses and theories. That being said, EUT proponents are not opposed to experiments like some are; "Einstein was quite simply contemptuous of experiment, preferring to put his faith in pure thought." Paul Davies
This is a relatively new theory(<20yrs), and there is a little something called the Scientific Method; "a method or procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses."
Experiment comes after a couple of other steps, and as I pointed out on another thread, the experiments are forth coming.
Ask, hypothesize, predict, test, analyze. Damn the process!
barakn
5 / 5 (4) Nov 09, 2012
And the ad hominem and straw man arguments begin from the pseudo-skeptics.
barak, if your shoelaces have magnetic fields and emit EM radiation as the nebula is observed to have, you may be correct.
Yes, actually, they do emit EM radiation, mostly in the infrared. They also reflect a lot of visible light. And of course there are magnetic spins associate with the electrons themselves, their orbits, and with the atomic nuclei as well. So, case closed. My shoelaces are definitely a work of wonder from the electric universe. And as for "the ad hominem and straw man arguments," that presumes we're arguing with you. That's not what's happening - you're simply being mocked. You already lost the argument a long time ago in threads now dead.
cantdrive85
1 / 5 (5) Nov 09, 2012
It's no wonder you have such a hard time with science, with the inability to read into the meaning of simple sentences it's a wonder you can even spell the word "A". The nebula emits not only visible, and infrared, (because I said, "as the nebula is observed to have") but also radio, x-ray and synchotron radiation. Those must be some fabulous shoelaces. How do you tie them? Must be difficult to tie shoes with asbestos/ceramic oven mitts on. Reading comprehension is a valuable skill, Rube!
rubberman
not rated yet Nov 09, 2012
I can't tell what the EU guys are debating here, of course all of the terms CD85 pulled from the article are plasma terms, the stars are in a Nebula, they are surrounded by plasma. The two dwarfs tightly orbiting around a center of gravity, causing symmetrical "jet" formations in the plasma makes sense assuming a uniform density of the plasma, independant of the material originating in an accretion disk around one of the dwarfs. (The magnetic fields in binary systems can be amplified due to the interaction between the two stars, especially if one is highly conducting, this is referred to as the common envelope )See paper entitled:
"Magnetic field evolution of white dwarfs in strongly interacting binary"

I can't link the paper directly, but a google search for the above takes you there.

The paper describes the field as axissymmetrical and will increase in strength as the orbital decay increases.

barakn
5 / 5 (1) Nov 09, 2012
Oh, poor thing. You still think you're being argued with. I don't give a hoot what frequency the EM is at.
cantdrive85
1 / 5 (4) Nov 09, 2012
Get that reading comprehension to improve, and maybe someday you'll figure it out.
A2G
3 / 5 (2) Nov 11, 2012
A2G, there is a great deal of information about plasma and it's characteristics, research has been going on for over a hundred years now (not only in your imaginary lab).

hahahahahahaha....You are about to find out how incredibly ignorant you truly are. The real problem you have is your delusion that you believe that you actually know what you are talking about. Your approach may work with the scientifically challenged layman such as yourself, but the real scientists know you EUT guys are full of it within about 30 minutes of looking at your own materials.

One of your websites just put up a new article on how electricity is at work on Io. Are you freaking insane? You do realize that we now have hi-res images and data of Io that totally disprove that whole concept don't you?

I think you should choose to stick with the study of mythology.

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