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B New theory, our solar system formation, "space bubble".

  1. Dec 23, 2017 #1
    "There are various theories about how the solar system formed, but scientists haven't been able to agree on a single model that explains all the quirks of our corner of space as it exists today. Now, scientists at the University of Chicago have come up with a new model that explains an enduring mystery about the early solar system. They hypothesize that our solar system formed inside a massive space bubble, which was produced by a star 40 to 50 times the size of our sun. The research was published today in Astrophysical Journal."

    bubble.jpg

    [​IMG]

    From https://www.engadget.com/2017/12/23/solar-system-formation-wolf-rayet-star/
     
  2. jcsd
  3. Dec 23, 2017 #2

    Delta²

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    How big exactly was the mother star (Wolf Rayet type star)??? IF (I know this is not the case I just say if) its center was the same as the center of our sun would it reach up to where earth is now?

    EDIT: Ok I guess not that big, maybe up to where mercury is...
     
    Last edited: Dec 23, 2017
  4. Dec 23, 2017 #3

    stefan r

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    They can have radius less than the sun. For example WR142, or WR2
     
  5. Dec 23, 2017 #4

    Delta²

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    Ok thanks, when I first read the article, I read 50 times bigger than Sun I thought that was referring to the radius of the stars, but I guess it was referring to the total mass of the stars.

    Can you help me understand the picture a bit. It says the bubble is in what I identify as the "blue fluid". What the blue fluid is exactly? Also if you can explain briefly what the other components in the picture are, e.g the molecular cloud...
     
  6. Dec 23, 2017 #5

    stefan r

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    molecular cloud. there are books on this topic.

    I think the blue part is just a stellar wind. The graph looks strange on my computer. The colors should be labeled better IMO.
     
  7. Dec 23, 2017 #6

    Delta²

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    Ok the link for stellar wind says that it is ejected by the upper atmosphere of a star. Let me see If I get the basics of this picture right, the star is represented by the bright little sphere in the center of the picture? Or the star is the whole picture (including the molecular cloud)??
     
  8. Dec 25, 2017 #7

    stefan r

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    The x and y axis are labeled R(cm). The video changes the length scale between frames. It it is really 1020 then radius is the image is supposed to be around 100 light years. The top line says "Density, t= ...E6" t is rolling forward so I assume time in years. So density must be the colors. The numbers by the color scale change and they change to fast to make sense of them. But they are sequential.

    Over 4 million years the star goes from type O to red supergiant and ends and wolf-rayet.

    I am a bit skeptical. There is something strange happening at x=0.
     
  9. Dec 25, 2017 #8

    jim mcnamara

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    I agree with @stefan r - The graphics are confusing, a priori, ...trying to find some clarification.
     
  10. Dec 26, 2017 #9

    Bandersnatch

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    Here you can see the same simulation running over a longer period of time with some explanations:
    http://astro.uchicago.edu/~vikram/Media/bub40.mov
    It looks like one of simulations of behaviour of molecular cloud medium under shockwaves from dying stars, like e.g. those seen here:
    https://arxiv.org/abs/1111.0012

    Here's my best attempt at reading the study:
    The graph shows the effects of the stellar wind from a star, in the latter stages of its life, on a molecular cloud in which it is embedded.
    The star is too small to show on the scale of the graph.
    The extended video above has the bubble expand from approx 20 lyr radius at the end of main sequence, to ~100 lyr by the end of the W-R phase.
    The star blows away material in a bubble around itself. This results in a low-density region (in blue) in its immediate vicinity, and a compressed shell (bright yellow) of molecular cloud material (darker yellow). Whenever you see brighter colours (towards the top of the scale), it means there's more material there, and vice versa.
    Over time, and as stellar emissions go up, the bubble expands.
    Due to various ratios of mass loss and velocity, the flow of material ejected from the star penetrates the shell to varying degrees.
    The high-mass loss, high-velocity Wolf-Rayet flows allow the material abundant in the ejecta at this stage of stellar life (specifically, isotopes of aluminium) to penetrate the shell, and the additional compression gives rise to overdense regions in the cloud which will later nucleate new stars. The W-R stage is the last 0.2 million years of the simulation - it's the final, strongest blow seen in the animation.
    The ejecta of the subsequent supernova (not shown), which include isotopes of iron, don't penetrate the shell as well, which would explain the relative overabundance of aluminium vs iron we have in our solar system - and this is what the study aims to show.
     
    Last edited: Dec 26, 2017
  11. Dec 26, 2017 #10

    Delta²

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    big thanks @Bandersnatch this answers a lot of questions that had been gathered in my mind.
     
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