Solution to a long-standing solar mystery?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Dec 13, 2016.

  1. paddoboy Valued Senior Member

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    Researchers report possible solution to a long-standing solar mystery
    December 13, 2016 by Jeff Kuhn

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    An image of the sun taken with The Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory spacecraft. HMI is an instrument designed to study oscillations and the magnetic field at the solar surface, or photosphere. HMI observes the full solar disk with a resolution of 1 arcsecond. Credit: NASA
    Astronomers from the University of Hawaii Institute for Astronomy (IfA), Brazil, and Stanford University may have solved a long-standing solar mystery.

    Two decades ago, scientists discovered that the outer five percent of the sun spins more slowly than the rest of its interior. Now, in a new study, to be published in the journal Physical Review Letters, IfA Maui scientists Ian Cunnyngham, Jeff Kuhn, and Isabelle Scholl, together with Marcelo Emilio (Brazil) and Rock Bush (Stanford), describe the physical mechanism responsible for slowing the sun's outer layers.




    Read more at: http://phys.org/news/2016-12-solution-long-standing-solar-mystery.html#jCp
     
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  3. paddoboy Valued Senior Member

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    https://arxiv.org/ftp/arxiv/papers/1612/1612.00873.pdf

    A Poynting-Robertson-like drag at the Sun’s surface:

    ABSTRACT:

    The Sun’s internal rotation Ω(�, Θ) has previously been measured using helioseismology techniques and found to be a complex function of co-latitude, θ, and radius, r. From helioseismology and observations of apparently “rooted” solar magnetic tracers we know that the surface rotates more slowly than much of the interior. The cause of this slow-down is not understood but it is important for understanding stellar rotation generally and any plausible theory of the solar interior. A new analysis using 5-min solar p-mode limb oscillations as a rotation “tracer” finds an even larger velocity gradient in a thin region at the top of the photosphere. This shear occurs where the solar atmosphere radiates energy and angular momentum. We suggest that the net effect of the photospheric angular momentum loss is similar to Poynting-Robertson “photon braking” on, for example, Sun-orbiting dust. The resultant photospheric torque is readily computed and, over the Sun’s lifetime, is found to be comparable to the apparent angular momentum deficit in the near-surface shear layer.
     
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  5. nebel Registered Senior Member

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    To repeat on my earlier posts. The 5min solar oscillation, when converted to distance using "c" as a measure of wavelength, shows that this eqBals the maximum difference possible between planetary diameters, orbits, ~ .3 AU. in our planetary system. There appears to be a link between planetary spacings and stellar oscillations. --but correlation is not causation, perhaps stabilisation though, needed for life to evolve long enough --to us.
    P.S. There is an opposite to the Poynting Robertson effect, where prograde rotation will provide thrust in direction of the orbit direction.
     
    Last edited: Dec 14, 2016
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  7. origin Trump is the best argument against a democracy. Valued Senior Member

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    To repeat my reply this is just numerology and not science.
     
  8. nebel Registered Senior Member

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    o: numbers that with better the 5% accuracy predict all planetary orbits and link it to the abovementioned 300 seconds stellar oscillation. curious coincidences in scientific figures. not less, possibly more.
     
  9. paddoboy Valued Senior Member

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    No.
     
  10. nebel Registered Senior Member

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    The Yarkovsky effect, from the sun (oscillating at 300 secs) through rotation to translation. Another stellar period generated radial spacing reported on apod Dec 11 2016. ont 300seconds but 800 years.
     
    Last edited: Dec 15, 2016
  11. paddoboy Valued Senior Member

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    None of that has anything to do with the OP subject re the outer five percent of the sun spinning more slowly than the rest of its interior. I will also add that the Sun's surface also rotates at the Equator, faster then it does at the Poles.
     
    danshawen likes this.
  12. nebel Registered Senior Member

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    we don't know thatfor sure, the last world has not been said on any of this, The sun exerts a tremendous influence through all its oscillations, inside and outside, and the study is about the prominent 5 minute effect.
     
    danshawen likes this.

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