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Magnetic Fields Dominate Young Stars of all Sizes?

by Anne Minard on June 11, 2009

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Image courtesy of Manel Carrillo, Josep Miquel Girart (CSIC-IEEC), Nimesh Patel (SMA), Spitzer

Image courtesy of Manel Carrillo, Josep Miquel Girart (CSIC-IEEC), Nimesh Patel (SMA), Spitzer

When it comes to the role of magnetism in the formation of stars, size might not matter.

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A team of researchers led by Josep Girart, of the Institut de Ciències de l’Espai (in Spain), studied the slow evolution of a dust cloud into a massive star, and realized that the cloud’s magnetic field controls the star’s development more than any other factor. They propose that the story is the same for small stars — an idea that could offer a new way to understand the formation of the early universe.

The new hypothesis is presented in this week’s issue of the journal Science, and the lead image represents an artist’s rendering of the concept.

The background shows a false-color Spitzer image of the massive star-forming region G31.41, with the colors indicating various wavelengths of light.  The zoom-in region represents the dust emission from the massive hot core (color and contour image) superposed with bars showing the structure of the magnetic field.

Pictured in the bottom of the image is the Submillimeter Array in Hawaii, which was used for the observations.

The authors describe how the magnetic field at G31.41 has deformed the dust cloud into an hourglass shape – a telltale sign of magnetically controlled star formation.

They say that this magnetic energy dominates over the other energies at play — e.g., centrifugal force and turbulence — and suggest that the role of the magnetic field in the early stages of star formation could be very similar for both small and massive stars.

“The energetic relations do not differ too much” between massive and small stars, the authors write. “Both cores are collapsing because gravity has overcome pressure forces, but the collapsing dynamics are controlled by the magnetic energy rather than by turbulence.”

Girart and his colleagues point out that this only holds true for forming stars; older massive stars are more influenced by radiation and ionization pressure, turbulence, and outflows than by magnetic fields.

Massive stars play a crucial role in the production of heavy elements and in the evolution of the interstellar medium, so this discovery might eventually lead to new insights about the formation of the early universe.

Source: Science

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  • Nereid2

    @Anaconda: thanks for your comments on synchrotron radiation.

    Synchrotron radiation is a type of electromagnetic radiation that can be emitted over different parts of the electromagnetic wave spectrum. It is a product of ultrarelativistic (i.e., moving near the speed of light) electrons spiralling around a magnetic field. A couple of its characteristics are non-thermal radiation and polarization.

    It was predicted to exist in space by Hannes Alfven, 1970 Nobel Prize winner, and his associate in 1950, six years before it was actually detected by 1956 by Geoffrey R. Burbidge.

    It can be detected by astromomical instruments and has been for over 60 years.

    But as usual Nereid wants to distract from the relevant issue. Synchrotron radiation is a signature of Z-pinches and it CAN be detected, but apparently it wasn’t determined if present in this paper.

    Just a couple of (pedantic?) clarifications, if I may …

    First, any charged particle can emit synchroton radiation, not just electrons. In astrophysics synchrotron radiation from electrons is more likely to be seen than that from iron ions, say, or positrons, but these two most certainly *can* produce synchrotron radiation. If you’d like more details, just ask, and I’ll be happy to provide them.

    Second, ‘spiralling around’ is a bit of an overkill; all a charged particle needs to do to emit radiation is accelerate (though polarisation happens only if there is some preferred direction).

    So let’s talk about “ultrarelativistic (i.e., moving near the speed of light)” charged particles moving in magnetic fields, shall we?

    A good place to start might be the huge amount of observational evidence that points to the ubiquity of magnetic fields throughout the ISM … I expect this is not a topic which you, Anaconda, will make a sharp comment on, and demand that I provide copious references to back up my statement … (but, as always, I could be wrong).

    Now what about ultrarelativistic charged particles? Well, they exist, and in quite some abundance … they’re called cosmic rays.

    So, there should be no doubt whatsoever that the sky is bathed in synchrotron radiation from cosmic rays ‘spiralling around’ the magnetic fields which pervade the ISM (and the solar system, and the Earth’s magnetosphere, and …), right Anaconda?

    Next: if this is so (and if I’m wrong I trust that you’ll tell me so quickly Anaconda), then the detection of synchrotron radiation from the direction of G31.41 is a no brainer … the astonishing news would be if no synchrotron radiation were detected!

    But, as you say Anaconda, if there is a z-pinch out there, somewhere, in or around G31.41, there should be some synchroton radiation; how, then, to distinguish between that which comes from cosmic rays and that which comes from the z-pinch (if it exists)?

  • Nereid2

    Here’s some words by Nereid2 that Anaconda has been dying to read … space is pervaded by vast numbers of electric currents!

    In some detail, the pedantic details …

    What is an electric current?

    At Anaconda’s preferred level of understanding, it is a movement, or flow, of electrically charged particles. Further, an electric current is proportional to the speed of the particles, as well as the charge of the particles. So if we have a highly charged particle – an fully ionised iron ion say – moving at ultrarelativistic speed, then the current will be far greater than an electron moving very slowly.

    What are cosmic rays?

    They are charged particles, moving at ultrarelativistic speeds. Some of these particles are fully ionised iron ions, some are even fully ionised lead ions; some are electrons, and some are positrons (and so on).

    It follows then, from the defintion of an electric current, that cosmic rays are currents.

    Now since cosmic rays seem to pervade space (at least within the Milky Way galaxy, and certainly the solar system), it follows, logically, that there are vast numbers of electric currents in space (and since most of space is filled with plasma, there are vast numbers of electric currents in space plasma).

    Am I right, Anaconda? Did I get the threshold question right?

  • Nereid2

    @DrFlimmer:

    Oh, and btw. According to special relativity it is possible to transform oneself into the system of rest of the current, hence in this system there is no current and no magnetic field – but in other systems you have a magnetic field. This in turn leads to the interpretation that magnetic and electric fields are just two sides of the same coin. But this another story and to explain you this, I need more than simple calculus, what even a school boy should understand.

    In an earlier comment of mine – on some other UT story I think – I introduced this too; Anaconda’s response, IIRC, was essentially “I don’t understand what you’re talking about, you’re just trying to obfuscate, and in any case I have no interest in learning anyway” (not his exact words of course, but I think the tone and meaning is fairly accurately summarised).

    His “I’m ignorant, I know I’m ignorant, I’m proud of my ignorance, and I have no intention or desire to change anything” attitude continues to shock me.

  • Nereid2

    @rFlimmer: I stumbled on this webpage; it gives the four pages of Fermi’s notebook where he worked out his idea on the cosmic ray acceleration mechanism (later published in his 1949 paper).

    http://www.symmetrymagazine.org/cms/?pid=1000231

    It doesn’t address your question, I know, but I think it’s pretty cool …

  • IVAN3MAN

    @ Nereid2,

    If you think that Anaconda’s ignorance is shocking, wait until you see the “fake doctored [Moon landing] photos” rambling diatribe by “Neil” on the “Shuttle delayed until July, LRO goes up Thursday” thread at Bad Astronomy. :roll:

  • Nereid2

    @IVAN3MAN: at least with Anaconda there is, at last, some common ground on which to build, in terms of mutually agreed words etc … IOW, meaningful communication is at least possible.

    IMVHO, with hoaxers/deniers/conspiracy theorists/etc one cannot engage in meaningful communication, period (you think you’re speaking the same language, but you’re not).

    And the gulf cannot, I think, be bridged. Why? Because meaningful communication requires common ground on how to deal with the problem of induction (sure the Sun rose this morning, and yesterday, and … but how do you *know* it will rise tomorrow?). Vast swathes of language work principally by mutual acceptance that the meanings of words – and phrases and so on – can be generalised beyond the immediate, very narrow meaning in each particular use (this leaf on this tree is green, that leaf on the same tree is green, this leaf on that tree is green, … -> mutual acceptance of ‘green’ in general).

    My impression – which, it goes without saying, could be wrong – is that at the heart of each confirmed conspiracy theorist’s (CT) thinking is a big red ‘I REFUSE TO GENERALISE’ button, which can be pressed at any time, for any reason … and it used with considerable frequency when it comes to the intentions of others.

    Elwood Herring, post#11, has it in a nutshell:

    Some people would deny the moon landings even if they were magically transported there and had their thick skulls banged repeatedly against the remnants of the landing craft.

    Try this (if you haven’t already): ask a CT to *commit* to providing clear, unambiguous criteria for ‘proving me wrong’ (i.e. there is, and was, no conspiracy). I doubt that any CT would do so, and if any did, the criteria would amount to ‘I cannot be proven wrong, ever, under any circumstances’.

  • IVAN3MAN

    Nereid2:

    Try this (if you haven’t already): ask a CT to *commit* to providing clear, unambiguous criteria for ‘proving me wrong’ (i.e. there is, and was, no conspiracy). I doubt that any CT would do so, and if any did, the criteria would amount to ‘I cannot be proven wrong, ever, under any circumstances’.

    Somebody on that thread has already asked that from “Neil”, but his response was sadly predictable:

    Granted subpoena power, an independent, fully funded and fully empowered investigation could acquire proof of the Apollo hoax. I could acquire it in a day.

    :roll:
    These conspiracy nutters (mostly men, but some women too!) are like kids in the schoolyard: they want to believe in some major conspiracy because they think that they are somehow empowered when they are in possession of some ‘classified information’.

    Furthermore, due to their low self-esteem, they are unwilling to give up their delusion, despite the overwhelming evidence against their belief, because that will take away from them their ‘power’ — it is like depriving a drug addict of his/her ‘fix’. You cannot reason with a drug addict!

    At least with Anaconda, he serves as a “Devil’s advocate” and prompts one to do more research whenever he asks awkward questions, but even he shows total stubbornness when you provide the mountain of evidence against his assertions, which he fails to acknowledge, and he just parrots the same questions again on another “modern” (as he calls it) astronomy post.
    :roll:

  • ND

    I’m going to summarize some of the points brought up in this post. Please correct me so this summary is correct as I am skimming a bit on the multitude of posts in this thread. There have been some important points made in this thread worth summarizing. I think the summary is light on the physics of synchrotron radiation.

    - A magnetic field can be created by something other than a current of charged particles. This according to Maxwell’s equations. A changing electric field can generate magnetic fields.

    - Beyond our solar system, if an electric current is generating a magnetic field, it is difficult to calculate this current simply by the magnetic field measurements. We are constricted by the limits of astronomical measurements. What else is new in Astronomy. What astronomer would not love to have probes orbiting nearby stars and interstellar space. Hey at least we can see back in time ;) A 3D observational view of such of the magnetic field would be a good first step.

    - Polarization in light is used to measure magnetic fields beyond our solar system. Polarisation can also be caused by objects between us and the object being measured (this adds to uncertainty?).

    - Given the difficulty in calculating currents beyond our solar system, the EU/PC claim that new observations support currents in space cannot be scientifically supported at this time.

    - The paper does not discuss Z-pinches. The observational data in the paper is not enough to come to such a conclusion. The hourglass shape of the magnetic field can be explained by the shape of the cloud itself. In other words a collapsing cloud could be deforming the magnetic field into an hourglass shape. Further observations should be done to detect things like synchrotron radiation.

    - Magnetic fields are involved in the formation of stars and this has been part of star formation models for quite a while.

    - There can never be enough observations and data points. Just to throw that one in there :)

  • Anaconda

    …well…well…well…when the cat’s away the mice will play :-)

    Nereid don’t be passing out false information on this website.

    ND states: “- A magnetic field can be created by something other than a current of charged particles. This according to Maxwell’s equations. A changing electric field can generate magnetic fields.”

    False.

    Dr. Eugene N. Parker acknowledges the requirement of Maxwell’s equations that electric currents cause magnetic fields:

    “…magnetic fields appear only in association with electric currents…”

    And, “In the laboratory we create static magnetic fields by driving an electric current through a coil of wire. The emf [electromotive force, 10^39 more powerful than gravity] and the current are clearly the CAUSE [original emphasis] of the magnetic field.” (p. 25, Conversations)

    So, Dr. Parker acknowleges that, here, on Earth in the laboratory electric currents are the cause and magnetic fields are the effect, not the other way around.

    But Dr. Parker does immediately state in the next sentence: “On the other hand, in the cosmos the deformation of the magnetic field embedded in the swirling plasma causes the flow of electric current in the plasma…” (p.25)

    The reason for this difference is the assumed difference of the terrestial environment and space as Dr. Parker expressed: “The air that we breathe is an example and only upon reaching the ionosphere does MHD [magnetohydrodynamics] become effective.” (p.3 Conversations)

    There are several problems with this assertion:

    Dr. Parker cites no experiments for his proposition, but relies on a priori mathematical extrapolation for his hypothesis. In other words, instead of in situ observation & measurements or in situ experiments, Dr. Parker relies on mathematical ‘thought experiments’ as justification.”

    Nereid, it is very bad form to pass out false infomation Eugene N. Parker would not approve of your conduct.

    http://books.google.com/books/p/princeton?id=7gJ_i3CTcpQC&printsec=frontcover&source=gbs_ViewAPI&hl=en

    ND states: “- Given the difficulty in calculating currents beyond our solar system, the EU/PC claim that new observations support currents in space cannot be scientifically supported at this time.”

    No that is false. More information is needed such as whether synchrotron radiation is detected.

    There is no experimental evidence that a magnetic field can stand in isolation without an electric current to generate it.

    Following the empirical Scientific Method’s axiom: to understand the unknown one needs to compare it with the known.

    There is no known experimentally or observationally verified instance of a magnetic field standing without an underlying electric current, Period.

    So, the reasonable inference is that ALL magnetic fields in the Universe are supported by electric currents.

  • IVAN3MAN

    Anaconda, you would NOT know electric currents from black currants! :P

  • IVAN3MAN

    Anaconda:

    Dr. Eugene N. Parker acknowledges the requirement of Maxwell’s equations that electric currents cause magnetic fields:

    “…magnetic fields appear only in association with electric currents…”

    And, “In the laboratory we create static magnetic fields by driving an electric current through a coil of wire. The emf [electromotive force, 10^39 more powerful than gravity] and the current are clearly the CAUSE [original emphasis] of the magnetic field.” (p. 25, Conversations)

    So, Dr. Parker acknowleges [sic] that, here, on Earth in the laboratory electric currents are the cause and magnetic fields are the effect, not the other way around.

    So, Anaconda, you’re up to your old tricks of quoting out of context again, like your jive-ass friend, OilIsMastery, and cherry-picking those bits that support your assertions while ignoring the essential context of the article.

    Well, here’s the full and unadulterated context of that quote by Dr. Eugene N. Parker from chapter 3 on Magnetic Fields in his book Conversations on electric and magnetic fields in the cosmos:

    In the absence of magnetic charges, magnetic fields appear only in association with electric currents and in association with time varying electric fields, in the manner described by [equation 1.6]. In the laboratory we create static magnetic fields by driving an electric current through a coil of wire. The emf driving the current is the source of energy that creates the magnetic field, so the emf and the current are clearly the cause of the magnetic field. On the other hand, in the the cosmos the deformation of the magnetic field embedded in the swirling plasma causes the flow of electric current in the plasma in the manner described by [equation 1.6], because the energy that drives the current comes from the magnetic field. [...]

    Now here is the kicker:

    The curious popular notion that the electric current causes the magnetic field in the cosmos has led to the even more curious notion that the electric current is the more fundamental dynamical variable. [<< My emphasis.] Then, since currents are driven by electric fields, it is declared that the fundamental dynamical variables are E and j. As already noted, the difficulty is that there are no tractable dynamical equations for E and j. The current is dynamically passive, consisting of no more than the tiny inertia of the electron conduction velocity, while, as we shall see, the stresses in the electric field are small to second in v/c and quite negligible. The dynamics of the plasma-magnetic field system is driven by the magnetic stress and the inertia and pressure of the plasma.

    So, Anaconda, you’re a fraud, a charlatan, and a goddamn sophist rolled into one.

  • IVAN3MAN

    Anaconda:

    There is no experimental evidence that a magnetic field can stand in isolation without an electric current to generate it.

    Following the empirical Scientific Method’s axiom: to understand the unknown one needs to compare it with the known.

    There is no known experimentally or observationally verified instance of a magnetic field standing without an underlying electric current, Period..

    One word answer: Lodestone.

    :cool:

  • ND

    Well the cat has a tendency to go away when the questions get too tough.

    Anaconda: “There is no known experimentally or observationally verified instance of a magnetic field standing without an underlying electric current, Period.”
    Where do magnets fit into this then?

    Anaconda “ND states: “- Given the difficulty in calculating currents beyond our solar system, the EU/PC claim that new observations support currents in space cannot be scientifically supported at this time.”

    No that is false. More information is needed such as whether synchrotron radiation is detected.”

    *double take*, are you saying no and then yes? Your brief response isn’t clear to me.

    As for my summary. I was summarising what was discussed in this thread. And one of the points was that magnetic fields can be generated by something other than an electric current. If there are issues with anything in the summary I’m open to corrections, but I would prefer by those who have actually studied science (particularly Maxwell’s equations)

  • Nereid2

    Oh Anaconda, if only you had bothered to actually *read* what was written while you were away …

    Here’s some words by Nereid2 that Anaconda has been dying to read … space is pervaded by vast numbers of electric currents!

    And who wrote that?

    Why Nereid2 did! (UT date June 20th, 2009 at 11:22 am)

    More information is needed such as whether synchrotron radiation is detected.

    And I actually started to do the scientific grunt work for you, on investigating the question of the detection of synchrotron radiation from the direction of G31.41(no UT date this time, you go look it up).

    There is no known experimentally or observationally verified instance of a magnetic field standing without an underlying electric current, Period.

    Ah yes, so by now we have pretty solid evidence that is consistent with the hypothesis that you are not only ignorant Anaconda, but also dishonest to boot.

    You see I walked you through an example of a well-detected magnetic field, and asked you where the associated current is … but you chose to not answer.

    Then DrFlimmer added some more stuff on the same topic … but you chose to not answer.

    Finally I followed up with the example of light (electromagnetic radiation) – which is, of course, an extremely known experimentally AND observationally verified instance of a magnetic field standing without an underlying electric current – but you chose to not answer.

    So, Anaconda, the game is up … your dishonesty has been objectively revealed, and it would seem that you are merely a troll.

    Now there may be a perfectly innocent explanation for your not answering any of the specific, and detailed, comments which address your misunderstandings and ignorance, so why not take the time to read ALL the comments in this thread? If there’s stuff you don’t understand, then by all means ask questions. And if you find that you’ve shot your mouth off, your apologies would go a long way to having the ‘troll’ label removed from you.

  • IVAN3MAN

    Nereid2:

    So, Anaconda, the game is up … your dishonesty has been objectively revealed, and it would seem that you are merely a troll.

    The Troll’s Brain and MEMORY.

  • DrFlimmer

    Well, I wondered if I would get an answer for my post from

    June 20th, 2009 at 8:18 am.

    Sadly, nothing happend, and Anaconda just went the way we all should have known that he would go!

    He is not even interested in the paper (it only contains two minor equations, so it is even easy for you!). Two have asked so far, btw….

    There is nothing more to add, everything is said by others.

    So, Anaconda. I would like to read a reaction to my comments from the specific post that I mentioned above. I’ll be waiting…

  • IVAN3MAN

    Anaconda: **CRICKETS**

  • Anaconda

    Well, Nereid I’m glad to see you acknowledge electric currents in space, but it is more than cosmic rays, it is organized “flows” of electrons and ions.

    Ivan3Man, I see that you are okay with distortion. I linked the Parker citation so you could review it and you did. Good boy :-)

    And I stated Dr. Parker’s paper in summarized fashion and did in fact mention that he proposed a hypothesis that magnetic fields stand in the plasma.

    Nereid, It should have been obvious from Parker’s paper that the discussion is about electrons and ions and emf (electromotive force), not the electromagnetic wave spectrum and by the way “light” or X-rays, or what have you doesn’t generate a magnetic field.

    Never mind Nereid that never stopped her before.

  • DrFlimmer

    and by the way “light” or X-rays, or what have you doesn’t generate a magnetic field.

    This was not about light creating a magnetic field. This was about light BEING an oscillating electric and magnetic-field. (One can derive this VERY easily by applying Maxwell’s laws for the vaccum case (j and rho equaling zero).

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