Abstract
Irradiance variability has been monitored from space for more than two decades. Even though data come from different sources, it is well established that a temporal variability exists ≈0.1%, in phase with the solar cycle. Today, one of the best explanations for such an irradiance variability is provided by the evolution of the solar surface magnetic fields. But if some 90–95% can be reproduced, what would be the origin of the 10–5% left? Non-magnetic effects are conceivable. In this paper we will consider temporal variations of the diameter of the Sun as a possible contributor for the remaining part. Such an approach imposes strong constraints on the solar radius variability. We will show that over a solar cycle, variations of no more than 20 mas of amplitude can be considered. Such a variability – far from what is reported by observers conducting measurements by means of ground-based solar astrolabes – may explain a little part of the irradiance changes not explained by magnetic features. Further, requirements are needed that may help to reach a conclusion. Dedicated space missions are necessary (for example PICARD, GOLF-NG or SDO, scheduled for a launch around 2008); it is also proposed to reactivate SDS flights for such a purpose.
Similar content being viewed by others
References
Abbot, C. G.: 1942, Ann. of the Obs. Smithsonian Inst. 6, 163.
Callebaut, D. K., Makarov, V. I., and Tlatov, A.: 2002, ESA SP-477, 209.
Dikpati, M. and Gilman, P.: 2001, Astrophys. J. 552, 348.
Emilio, M., Kuhn, J. R., Bush, R. I., and Scherrer, P.: 2000, Astrophys. J. 543, 1007.
Ermolli, I., Berrilli, F., and Florio, A.: 2003, Astron. Astrophys. 412, 857.
Foukal, P.: 1992, in “The Solar Cycle”, ASP Conf. Ser. 27, 439.
Fröhlich, C.: 2000, ESA SP-463, 665.
Fröhlich, C. et al.: 1997, Solar Phys. 170, 1.
Kuhn, J. R.: 2004, Adv. Space. Res. 34, 302.
Kuhn, J. R., Bush, R., Scheick, X., and Scherrer, P.: 1998, Nature 392, 155.
Kuhn, J. R. et al.: 2004, Astrophys. J. 613, 124-1, DOI 10.1086/423301.
Krivova, N. A., Solanki, S. K. et al.: 2003, Astron. Astrophys. 399, L1–L4.
Lefebvre, S.: 2003, Ph.D. Thesis, Université de Nice Sophia-Antipolis, 228 p.
Lefebvre, S. and Rozelot, J. P.: 2004, Astron. Astrophys. 419, 1133.
Lefebvre, S., Bertello, L., Ulrich, R. K., Boyden, J. E., and Rozelot, J. P.: 2004, Proceedings of ESA, SOHO14-GONG2004 meeting, to be published.
Li, L. H., Basu, S., Sofia, S., Robinson, F. J., and Demarque, P.: 2003, Astrophys. J. 591, 1267.
Pap, J. M., Turmon, M., Shelton, K. E., Floyd, L. E., and Helizon, R.: 2003, AGU Fall Meeting, SH32A-1099.
Pap, J.: 2003, in “The Sun’s Surface and Subsurface”, Rozelot, J. P. (ed.), LNP, 599, Springer, 129.
Rozelot, J. P. and Lefebvre, S.: 2003, in “The Sun’s Surface and Subsurface”, Rozelot, J.P. (ed.), LNP, 599, Springer, 4.
Rozelot, J. P., Lefebvre, S., and Desnoux, V.: 2003, Solar Phys. 217, 39.
Rozelot, J. P. and Sofia, S.: 2004, Proposal to the UE 6th PCRD program.
Schou, J.: 2003, in M. Thompson and J. Christesen-Dalsgaard (eds.), Stellar Astrophysical Fluid Dynamics, p. 247, Cambridge University Press.
Sofia, S., Heaps, W., and Twigg, L. W.: 1994, Astrophys. J. 427, 1048.
Sofia, S., O’Keefe, J., Lesh, J. R., and Endal, A. S.: 1979, Science 204, 1306.
Solanki, S. K. and Fligge, M.: 2002, Adv. Space Res. 29, 1933.
Solanki, S. K. et al.: 2004, this issue, 197–208.
de Toma, G., White, O. R., Chapman, G. A., Walton, S. R., Preminger, D. G., Cookson, A. M., and Harvey, K. L.: 2001, Astrophys. J. 549, L131.
de Toma, G., White, O. R., Chapman, G. A., and Walton, S. R.: 2004, Adv. Space Res. 34, 237.
Woodard, M. and Hudson, H. S.: 1983, Nature 305, 589.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Rozelot, J.P., Lefebvre, S., Pireaux, S. et al. Are Non-Magnetic Mechanisms Such As Temporal Solar Diameter Variations Conceivable for an Irradiance Variability?. Sol Phys 224, 229–235 (2004). https://doi.org/10.1007/s11207-005-4975-9
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11207-005-4975-9