Researchers Propose New Model for the Most Eager Supernova Explosions

Article written: 8 Apr , 2009
Updated: 24 Dec , 2015
by

Type 1a supernovae like 2005ke, above, are known to go off when one member of a star pair exceeds critical mass and kickstarts a runaway fusion reaction.

Researchers have long puzzled over why some of the explosions happen so fast. Now, a team of Chinese astronomers believes they’ve arrived at a probable cause for the earliest of the blasts.

A team of astronomers, led by Bo Wang from the Yunnan Observatory of the Chinese Academy of Sciences, have shown how the transfer of material from a ‘helium star’ to a compact white dwarf companion causes these cataclysmic events to take place. The new results appear in Monthly Notices of the Royal Astronomical Society.
Most type Ia supernovae are believed to occur when a white dwarf  (the superdense remnant that is the end state of stars like the Sun) draws matter from a companion star orbiting close by. Previous theories for the origins of a Type Ia include an explosion of a white dwarf in orbit around another white dwarf, or an explosion of a white dwarf in orbit around a red giant star. 
When the white dwarf mass exceeds the so-called Chandrasekhar limit of 1.4 times the mass of the Sun, it eventually collapses and within a few seconds undergoes a runaway nuclear fusion reaction, exploding and releasing a vast amount of energy as a type Ia supernova. Due to their high and remarkably consistent luminosities, astronomers use these events as ‘distance indicators’ to measure the distances to other galaxies and constrain our ideas about the Universe.

Scientists have confirmed more and more type Ia supernovae, and found that about half of them explode less than 100 million years after their host galaxy’s main star formation period. But previous models for these systems did not predict that they could be this young — so Wang and his team set out to solve the mystery.

Employing a stellar evolution computer code, they performed calculations for about 2600 binary systems consisting of a white dwarf and a helium star, a hot blue star which has a spectrum dominated by emission from helium. They found that if the gravitational field of the white dwarf pulls material from a helium star and increases its mass beyond the Chandrasekhar limit, it will explode as a type Ia supernova within 100 million years of its formation. 

 “Type Ia supernovae are a key tool to determine the scale of the Universe so we need to be sure of their properties,” said research team member Zhanwen Han, also from the Yunnan Observatory. “Our work shows that they can take place early on in the life of the galaxy they reside in.”

The team now plans to model the properties of the companion helium stars at the moment of the supernova explosions, which could be verified by future observations from the Large sky Area Multi-Object fiber Spectral Telescope (LAMOST).

LEAD IMAGE CAPTION: Supernova 2005ke shown in optical, ultraviolet and X-ray wavelengths. When it was captured, this was the first X-ray image of a Type 1a, and it provided observational evidence that Type Ia come from the explosion of a white dwarf orbiting a red giant star. Credit: NASA/Swift/S. Immler

Source: Royal Astronomical Society. The paper is available here.


24 Responses

  1. Why do we need a new model when our present one explains the entire universe?

    “It’s disturbing to see that there is a new theory every time there is a new observation.” — R. Brent Tully, astronomer, 1989

    “We may now be near the end of the search for the ultimate laws of nature.” — Stephen W. Hawking, mathematician, 1988

    “We do not need a new theory because our present one explains everything.” — Richard P. Feynman, professor, 1988

    “It is the theory that determines what can be observed.” — Albert Einstein, mathematician, 1926

    “There is nothing new to be discovered in physics now.” — Lord Kelvin, physicist, 1895

  2. star grazer says

    The detonation of an object less than the diameter of Earth with a mass over
    Chandrasekhar limit of 1.4 is mind boggling!!! Before I retired, I used to tell co-workers not too knowledgable about nuclear weapons or Supernova type 1A, that the material that causes the detonation of a 1 megaton warhead is less than the diameter of a seedless watermelon!!
    I said imagine an object about diameter of the Earth(actually smaller) with a mass of
    1.4x that of the Sun, or 470k times more mass than the Earth, I said the entire Earth-size object IS the material that causes the detonation of a nuclear bomb, imagine the whole thing going off at once,,,,,,,,, this power is far too much for lay-people to fully understand!!!!! They think of the object the size of a watermelon, then look at a globe of the Earth, the difference in power is far too much for lay-people to grasp such power!!!!!,

  3. Member
    IVAN3MAN says

    RE: OilIsMastery

    The Troll’s Brain and MEMORY

  4. Ap says

    Wow,
    they are extremely powerful occurences. Do these create fairly big GRB’s but on a smaller scale compared to a pulsar merging supernove?
    Has anyone worked out the damage radius of a type 1a supernovae. How far does the blast extend out to?
    and how far would your planet have to be to be safe from the effects?

  5. Ken says

    Come on OillsMastery … just come out and say it …. “this is all pointless, god did it!” … we know you’re dying to say it.

  6. Astrofiend says

    # Ken Says:
    April 8th, 2009 at 9:53 pm

    “Come on OillsMastery … just come out and say it …. “this is all pointless, god did it!” … we know you’re dying to say it.”

    But then he wouldn’t be taken seriously! Oh, wait…

  7. UKDave says

    To AP

    A safe survivable distance for a supernova to the earth would not be less than 200 light years. It could be considerably more.

    Makes you realise what incredibly energetic events they are!

  8. Feenixx says

    I find this very exciting. As the available computing power keeps growing, new possibilities are being modeled fast.
    I don’t see it as overturning older findings – but rather as a deepening of the scratches science is making on the surface of what we want to find out.

    UKDave, Astrofiend, IVAN3MAN,
    please, could you accept that OIM lives in his own Universe, where different physics and conventions apply. If you could, and just let him state his observations and points of view, and be done with it, there’d be a lot less aggravation in these comment threads

  9. Jon Hanford says

    @ IVAN3MAN: great diagram of the biology of a Troll’s brain! (I hope that’s not an oxymoron.) Concerning the story, looks like some newly formed massive stars are ready to go( SN, that is), sooner than was previously thought. This could have observable consequences in the evolution of clusters of very young massive stars.

  10. Feenix,

    “could you accept that OIM lives in his own Universe”

    Can you please explain how asking a question and quoting your heroes is living in my own universe?

    Is that because in your universe no questions get asked?

  11. Mr.Obvious says

    star grazer…
    You’re right… the amount of power being released is hard to wrap your head around.
    Just when you think you have it, you begin to think about how dense the white dwarf is, and how strong those bonds are to survive the blast itself… in order for the process to start all over again.

    Oills… you perpetual malevolent *&[email protected]#!
    We could explain it all to you, but you still wouldn’t get it. Maybe you can look up when we use cepheid variables vs when we use 1a supernovae. It may just light the candle in the troll brain.

    Ivan…
    Great post. Nailed it perfectly. From short term memory through the semantic BS.

  12. Yael Dragwyla says

    jeffery keown — we simply don’t know whether there is life out there or how much of it. That’s one reason Kepler was launched recently, to try to find planets more or less the size of Earth in the life-zones of stars. If Kepler finds such worlds out there, then maybe we can make even more powerful space telescopes that can determine which of those worlds has oxygenated atmospheres — a sure sign of life in some form. A methane signature persisting over significantly more than 50 years would also signal that life might be there. Some day we might even send probes to the nearer stars to look at their systems up close and see if any planets in them have life. Right now, though, we’re sort of stuck with what we can get along those lines, which ain’t much. Stay tuned for further exciting developments . . .

  13. jeffery keown says

    What bothers me about the trolls and wackadoodles is that when I posted real a observation on Galaxy formation, it was ignored in favor of feeding the trolls.

    I’m all for challenging these folks, but:

    A. I’m not terribly good at it.

    B. We should discuss the posts, and not the commenters.

    But…

    C. I’m new here, and I shouldn’t complain.

  14. jeffery keown says

    If these 1a supernovas are so dangerous, might they be invoked to explain the dearth of life in the Universe? Perhaps the lack of life is due to exploding stars and the behavior of gas giants… we could be really isolated out here on the edges of the Milky Way.

    I’d love to think of every sun-like (or nearly so) star as bearing a full blown garden world like Earth, but maybe space is as barren as it seems. It’s awfully dangerous out there.

  15. Feenixx says

    OilIsMastery Says

    “Can you please explain how asking a question and quoting your heroes is living in my own universe?”

    1) You never quoted the only hero-figure ever in my life: Chief Joseph

    2) There is no connection between what I said and you asking a question. Your question was “Why do we need a new model when our present one explains the entire universe?” – however, your previous posts indicate to me that you don’t believe that our present model explains everything.
    In my Universe, such a question, in the light of the views you hold, comes across as a provocative rhetoric device, rather than a genuine question… and I have no problem with it at all. I do it myself, occasionally.

    3) I proposed elsewhere on this site in a light-hearted manner that, in a manner of speaking, everybody lives in their own Universe, but that most people are unaware of this… which gives rise to never-ending pointless arguments, right down to destructive warfare.
    Do you realise that I virtually begged UKDave, Astrofiend and IVAN3MAN to lay off their ad hominem postings, to simply let you state your views and observations, and to leave it at that (rather than working up towards one of those endless bickering sessions)?

    you then say:
    “Is that because in your universe no questions get asked?”

    It simply isn’t true that in my Universe no questions get asked. I hope you can accept my word for it – I cannot prove it.

  16. Feenix,

    “Your question was “Why do we need a new model when our present one explains the entire universe?” – however, your previous posts indicate to me that you don’t believe that our present model explains everything.
    In my Universe, such a question, in the light of the views you hold, comes across as a provocative rhetoric device, rather than a genuine question… and I have no problem with it at all. I do it myself, occasionally.”

    If only you could be so accurate when it comes to interpreting mainstream dogma!

    ” I proposed elsewhere on this site in a light-hearted manner that, in a manner of speaking, everybody lives in their own Universe, but that most people are unaware of this… which gives rise to never-ending pointless arguments, right down to destructive warfare.”

    I laughed inside for a sec. But then how do you explain agreement between individuals?

    “Do you realise that I virtually begged UKDave, Astrofiend and IVAN3MAN to lay off their ad hominem postings, to simply let you state your views and observations, and to leave it at that (rather than working up towards one of those endless bickering sessions)?”

    There is nothing wrong with them criticizing my ideas. But when they devote their lives to devising new and creative ad hominem fallacies rather than using persuasive logical counterarguments, I think we both know what this says about the state of contemporary science.

    “It simply isn’t true that in my Universe no questions get asked. I hope you can accept my word for it – I cannot prove it.”

    This may come as a shock to you but I take your word for it. See how reasonable and persuadable I am?

  17. Member
    IVAN3MAN says

    @ Jon Hanford, and @ Mr. Obvious,

    Thanks! 🙂

  18. Feenixx says

    OilIsMastery Says:

    “I laughed inside for a sec. But then how do you explain agreement between individuals?”

    People in disagreement about some things does not rule out that they may agree on other things.
    You probably realise that I totally disagree with you on many points concerning Physics and Astronomy. But we do agree on an important issue: Neither of us believes that our current model explains everything.
    I’m only an enthusiastic amateur, but you know what: Not a single professional scientist of the many dozens I spoke to DOES believe that our current model explains everything.

    btw: I don’t want to make statements about the state of contemporary science – I haven’t studied this topic sufficiently, I’d be making a fool of myself.

  19. Feenixx says

    jeffery keown Says:

    “If these 1a supernovas are so dangerous, might they be invoked to explain the dearth of life in the Universe? Perhaps the lack of life is due to exploding stars and the behavior of gas giants…”

    hmmm…. I don’t actually see any evidence for any dearth of life in the Universe which may need explaining…. nor do I see evidence for abundance of life (even though I reckon there probably is life wherever it can hang on, but that’s only pipe dreaming, really, not science).
    How do you know there’s a dearth of life “out there”?
    No need to answer this question, I’m just posting it as something to think about.

  20. ND says

    Feenixx: “Not a single professional scientist of the many dozens I spoke to DOES believe that our current model explains everything.”

    Not according to the universe Anaconda and Oils live in. They’ve been debating people who hold this view and yet they continue to spout rhetoric and frankly prejudices about astronomers. I’m afraid it has not sunk in.

  21. Feenixx,

    “Not a single professional scientist of the many dozens I spoke to DOES believe that our current model explains everything.”

    Obviously you’ve never heard of Richard Feynman. He was and still is considered to be one of the most popular teachers of physics of the late 20th century. He clearly disagreed with you.

    “We do not need a new theory because our present one explains everything.” — Richard P. Feynman, professor, 1988

  22. Member
    IVAN3MAN says

    OilIsMastery:

    Obviously you’ve never heard of Richard Feynman. He was and still is considered to be one of the most popular teachers of physics of the late 20th century. He clearly disagreed with you.

    “We do not need a new theory because our present one explains everything.” — Richard P. Feynman, professor, 1988.

    Look, [matey], I took the liberty of examining that parrot, and I discovered that the only reason that it had been sitting on its perch, in the
    first place, was that it had been NAILED there!

    Oh, excuse me, I was thinking out aloud(!).

    Look, OilIsMastery, I took the liberty of Googling that ‘quote’ by Richard P. Feynman, and I discovered that the only reason he had stated it, in the first place, was that he had DISAGREED with Halton C. Arp!

    In other words, OilIsMarstery, you have quoted Richard Feynman out-of-context!

    This is what Halton Arp said about his conversation with Richard Feynman:

    Unfortunately, when I asked Feynman about the Hoyle-Narlikar variable mass theory, he told me, We do not need a new theory because our present one explains everything.

    So there!

  23. Feenixx says

    OilIsMastery, you say to me:
    “Obviously you’ve never heard of Richard Feynman. He was and still is considered to be one of the most popular teachers of physics of the late 20th century. He clearly disagreed with you.”

    I can’t figure out how it can be obvious to you that I never heard of Feynman. I never spoke to him, that’s all. In my comment, I wrote about “professaional scientists I spoke to”.

    Furthermore, had I spoken to him, and had he really had made such a statement, I would have challenged him on it. See, I challenge people if I (reasonably) don’t agree with a view they may hold, no matter how “big” they are, or how much I respect or even admire them… like I did recently with a well known and liked science author who occasionally posts comments here.
    As it happens, as IVAN3MAN already pointed out, you actually didn’t quote Feynman, you quoted Arp, talking about how Feynman disagreed with one of his ideas. I reckon that’s not fair.

  24. Jon Hanford says

    Besides the out of context quote between Feyman and Arp, I find your quote right on target -“Not a single professional scientist of the many dozens I spoke to DOES believe that our current model explains everything.” I would think that no self-respecting astrophysicist or cosmologist would make such an outlandish statement. Of course we don’t know everything about our universe, probably not even close. It’s precisely this lack of knowledge that drives science in the first place. If we had an infallable Theory of Everything (TOE) what would be the point of future scientific investigations?

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