Space Science Reviews

, Volume 94, Issue 1–2, pp 169–176 | Cite as

Using Precise Solar Limb Shape Measurements to Study the Solar Cycle

  • J.R. Kuhn
  • L. Floyd
  • C. Fröhlich
  • J.M. Pap


Despite 20 years of total solar irradiance measurements from space, the lack of high precision spatially resolved observations limits definitive answers to even simple questions like ``Are the solar irradiance changes caused solely by magnetic fields perturbing the radiative flux at the photosphere?" More subtle questions like how the aspheric structure of the sun changes with the magnetic cycle are only now beginning to be addressed with new tools like p-mode helioseismology. Solar 5-min oscillation studies have yielded precise information on the mean radial interior solar structure and some knowledge about the rotational and thermal solar asphericity. Unfortunately this progress has not been enough to generate a self-consistent theory for why the solar irradiance and luminosity vary with the magnetic cycle. We need sharper tools to describe and understand the sun's global aspheric response to its internal dynamo, and we need to be able to measure the solar cycle manifestation of the magnetic cycle on entropy transport from the interior to the photosphere in much the same way that we study the fundamentally more complex problem of magnetic flux transport from the solar interior. A space experiment called the Solar Physics Explorer for Radius, Irradiance and Shape (SPHERIS) and in particular its Astrometric and Photometric Telescope (APT) component will accomplish these goals.


Solar Cycle Solar Irradiance Total Solar Irradiance Flux Transport Magnetic Cycle 
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  1. Dearborn, D. S. P. and Blake, J. B.: 1980, Astrophys. J. 237, 616.Google Scholar
  2. Delache, Ph., Laclare, F. and Sadsaoud, H.: 1986, in J. Christensen-Dalsgaard and S. Frandsen (eds.), Advance in Helio-and Asteroseismology, IAU Press, p. 223.Google Scholar
  3. Fox, P. and Sofia, S.: 1994, in J. Pap, C. Fröhlich, H. S. Hudson and S. K. Solanki (eds.), The Sun as a Variable Star, Cambridge University Press, Cambridge, p. 280.Google Scholar
  4. Fröhlich, C. and Pap, J.: 1989, Astron. Astrophys. 220, 272.Google Scholar
  5. Fröhlich, C. et al.: 1997a, Solar Phys. 170, 1.Google Scholar
  6. Gililand, R. L.: 1980, Astrophys. J. 248, 1144.Google Scholar
  7. Kuhn, J. R.: 1996, in T. Roca Cortes (ed.), Global Changes in the Sun, in the VI Winter School at Instituto d’Astrophysica de Canarias, Cambridge University Press, Cambridge, p. 231.Google Scholar
  8. Kuhn, J. R., Libbrecht, K. G., and Dicke, R. H.: 1985, Astrophys. J. 290, 758.Google Scholar
  9. Kuhn, J., Bogart, R., Bush, R., Sa, L., Scherrer, P., and Scheick, X.: 1997, in J. Provost and F.-X. Schmieder (eds.), ‘Sounding Solar and Stellar Interiors’, IAU Symp. 181, 103.Google Scholar
  10. Kuhn, J.R., Bush, R., Scheick, X., and Scherrer, P.: 1998a, Nature 392, 155.Google Scholar
  11. Kuhn, J. R. et al.: 1998b, in C. Korendyke (ed.), SPIE’ 98, Missions to the Sun II, San Diego, CA, p. 203.Google Scholar
  12. Kuhn, J. R., Armstrong, J. D., Bush, R. I., and Scherrer, P.: 2000, Nature (in press).Google Scholar
  13. Laclare, F., Delmas, C., Coin, J.P., and Irbah, A.: 1996, Solar Phys. 166, 211.Google Scholar
  14. Lydon, T. J. and Sofia, S.: 1995, Astrophys. J. Suppl. 101, 357.Google Scholar
  15. Pap, J.: 1997, in C. Castagnoli and A. Provenzale (eds.), Past and Present Variability of the Solar-Terrestrial System: Measurement, Data Analysis and Theoretical Models, Enrico Fermi Summer Workshop, Italian Physical Society, p. 1.Google Scholar
  16. Parkinson, J. H., Morrison, L. V., and Stephenson, F. R.: 1980, Nature 288, 548.Google Scholar
  17. Ribes, E., Beardsley, B., Brown, T. M., Delache, Ph., Laclare, F., Kuhn, J. R., and Leister, N. V.: 1991, in C. P. Sonett, M. S. Giampapa, and M. S. Matthews (eds.), The Sun in Time, Arizona University Press., Tucson, p. 59.Google Scholar
  18. Sofia, S.: 1998, in J. M. Pap, C. Fröhlich, and R.K. Ulrich (eds.), Solar Electromagnetic Radiation Study for Solar Cycle 22, Kluwer Academic Publishers, Dordrecht, Holland, p. 413.Google Scholar
  19. Sofia, S., Heaps, W., and Twigg, L. W.: 1994, Astrophys. J. 427, 1048.Google Scholar
  20. Ulrich, R. and Bertello, E.: 1995, Nature 377, 214.Google Scholar
  21. Wehrli, C., Appourchaux, T., Crommelynck, D., Finsterle, W., Fröhlich, C., and Pap, J.: 1998, in F. J. Provost and F. X. Schmieder (eds.), ‘Sounding Solar and Stellar Interiors Poster Volume, OCAN, Nice’, IAU Symp. 181, 209.Google Scholar

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • J.R. Kuhn
    • 1
  • L. Floyd
    • 2
  • C. Fröhlich
    • 3
  • J.M. Pap
    • 4
  1. 1.Institute for AstronomyHonolulu
  2. 2.Interferometrics, IncChantilly
  3. 3.Physikalisch-Meteorologishes ObservatoriumDavosSwitzerland
  4. 4.Dept. Physics and Astronomy, UCLALos Angeles

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