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Long-lived giant cells detected at the surface of the Sun

Abstract

Giant convective cells have been predicted1 to exist in the Sun. Such cells should span the entire zone unstable to convective motions — now known to cover the outer 29 per cent of the Sun's radius2 — and could be dredging up the magnetic flux that is thought to be the source of solar activity (sunspots). Several studies3,4,5 have failed to detect these giant cells, although there have been hints6,7,8,9 of their existence. We have detected long-lived velocity cells, which we identify as the elusive giant convective cells, extending over 40–50 degrees of longitude but less than 10 degrees of latitude. The large aspect ratio (>4) is surprising (although predicted by one model10) and may be a consequence of the Sun's differential rotation, whereby features with a larger extent in latitude are broken up by rotational shear.

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Figure 1: Autocorrelation (a) and cross-correlation (b) of the time series for selected bins.
Figure 2: Maps of the east–west component of flow speed obtained by averaging over a disk passage.
Figure 3: The autocorrelation computed for the map of EPS Fig. 2 for the latitude 5± 5°.

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References

  1. Simon, G. W. & Weiss, N. O. Supergranules and the hydrogen convection zone. Z. Astrophys. 69, 435–450 (1968).

    ADS  Google Scholar 

  2. Christensen-Dalsgaard, J., Gough, D. O. & Thompson, M. J. The depth of the solar convection zone. Astrophys. J. 378, 413–437 (1991).

    Article  ADS  Google Scholar 

  3. LaBonte, B. J., Howard, R. & Gilman, P. A. An improved search for large-scale convection cells in the solar atmosphere. Astrophys. J. 250, 796–798 (1981).

    Article  ADS  CAS  Google Scholar 

  4. Snodgrass, H. B. & Howard, R. Limits on photospheric Doppler signatures for solar giant cells. Astrophys. J. 284, 848–855 (1984).

    Article  ADS  Google Scholar 

  5. Chiang, W.-H., Petro, L. D. & Foukal, P. V. Aphotometric search for solar giant convection cells. Sol. Phys. 110, 129–138 (1987).

    Article  ADS  CAS  Google Scholar 

  6. Cram, L. E., Durney, B. R. & Guenther, D. B. Preliminary observations of velocity fields at the solar poles. Astrophys. J. 267, 442–454 (1983).

    Article  ADS  CAS  Google Scholar 

  7. Hathaway, D. H. et al. GONG observations of solar surface flows. Science 272, 1306–1309 (1996).

    Article  ADS  CAS  Google Scholar 

  8. Simon, G. W. & Strous, L. H. Supergranular evolution, solar rotation, and a search for giant cells. Bull. Am. Astron. Soc. 29, 1402 (1997).

    ADS  Google Scholar 

  9. Ulrich, R. K. Large scale convection and the solar radius.In New Eyes to See Inside the Sun and Stars(eds Deubner, F.-L., Christnsen-Dalsgaard, J. & Kurtz, D. W.) (Proc. IAU Symp. 185, Kluwer, in the press).

  10. Snodgrass, H. B. & Wilson, P. R. Solar torsional oscillations as a signature of giant cells. Nature 328, 696–699 (1987).

    Article  ADS  Google Scholar 

  11. Brown, T. M. & Gilman, P. A. Techniques for detecting giant cells using spatially resolved solar velocity data. Astrophys. J. 286, 804–809 (1984).

    Article  ADS  Google Scholar 

  12. Scherrer, P. H. et al. The solar oscillations investigation — Michelson Doppler imager. Sol. Phys. 162, 129–188 (1995).

    Article  ADS  Google Scholar 

  13. Scherrer, P. H., Bogart, R., Hoeksema, J. T. & Yoshimura, H. in Seismology of the Sun and Distant Stars (ed. Gough, D. O.) 93–102 (Reidel, Dordrecht, (1986)).

    Book  Google Scholar 

  14. Gilman, P. A. Nonlinear boussinesq convective model for large scale solar circulations. Sol. Phys. 27, 3–26 (1972).

    Article  ADS  Google Scholar 

  15. Duvall, T. L. J, Harvey, J. W. & Pomerantz, M. A. Latitude and depth variation of solar rotation. Nature 321, 500–501 (1986).

    Article  ADS  Google Scholar 

  16. Schou, J. et al. Helioseismic studies with SOI-MDI of differential rotation in the solar envelope. Astrophys. J.(in the press).

  17. Nordlund, & & Aring;Dravins, D. Stellar granulation, III. Hydrodynamic model atmosheres. Astron. Astrophys. 228, 155–183 (1990).

    ADS  Google Scholar 

  18. Kim, Y.-C., Fox, P. A., Sofia, S. & Demarque, P. Modeling of shallow and inefficient convection in the outer layers of the sun using realistic physics. Astrophys. J. 442, 422–433 (1995).

    Article  ADS  Google Scholar 

  19. Freytag, B., Ludwig, H.-G. & Steffen, M. Hydrodynamical models of stellar convection; the role of overshoot in DA white dwarfs, A-type stars, and the sun. Astron. Astrophys. 313, 497–516 (1996).

    ADS  CAS  Google Scholar 

  20. Bai, T. Distribution of flares on the sun during 1955–1985; “hot spots” (active zones) lasting for 30 years. Astrophys. J. 328, 860–878 (1988).

    Article  ADS  Google Scholar 

  21. Duvall, T. L. J, D'Silva, S., Jefferies, S. M. & Harvey, J. W. Downflow under sunspots detected by helioseismic tomography. Nature 379, 235–237 (1996).

    Article  ADS  CAS  Google Scholar 

  22. Kosovichev, A. G. Tomographic imaging of the sun's interior. Astrophys. J. 461, L55–L57 (1996).

    Article  ADS  Google Scholar 

  23. Giles, P. M. et al. Asubsurface flow of material from the sun's equator to its poles. Nature 390, 52–54 (1997).

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

T.L.D. thanks P. Scherrer and the SOI group at Stanford for their hospitality during this work and for the use of their computing faciities, supported by NASA. SOHO is a mission of international cooperation between ESA and NASA. This work was supported in part by the Solar Physics Branch of the Space Physics Division of NASA.

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Correspondence to J. G. Beck.

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Beck, J., Duvall, T. & Scherrer, P. Long-lived giant cells detected at the surface of the Sun. Nature 394, 653–655 (1998). https://doi.org/10.1038/29245

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