Abstract
We investigate asymmetries of bipolar sunspot groups. We find that the magnetic field distribution of simple bipolar sunspot groups is significantly asymmetrical: the polarity inversion line is usually nearer to the main following polarity spot than to the main preceding one. This asymmetry grows with the age of the sunspot group. We suggest that this asymmetry has a causal link with two long-established asymmetries- the one in the proper motions of young sunspots, the other in the relative stability of p and f spots.
In our view, these asymmetries together indicate that emerging flux loops, making sunspot groups, are not symmetrical but tilted eastward. The tilt is presumably caused by drag forces due to radial differential rotation in subphotospheric layers. In this paper we present observational indications supporting this hypothesis.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Balthasar, H. and Wöhl, H.: 1980, Astron. Astrophys. 92, 111.
Balthasar, H., Schüssler, M., and Wöhl, H.: 1982, Solar Phys. 76, 21.
Bappu, M. K. V., Grigorjev, V. M., and Stepanov, V. E.: 1968, Solar Phys. 4, 409.
Brants, J. J. and Steenbeek, J. C. M.: 1985, Solar Phys. 96, 229.
Bray, R. J. and Loughhead, R. E.: 1964, Sunspots, Chapman and Hall, London.
Brunner, W.: 1913, Publ. Zürich Obs. 5, 1.
Carrington, R. C.: 1863, Observations of the Spots on the Sun from November 9, 1853, to March 24, 1861, Williams and Norgate, London and Edinburgh.
Chou, D.-Y. and Wang, H.: 1987, Solar Phys. 110, 81.
Chou, D.-Y. and Zirin, H.: 1988, Astrophys. J. 333, 420.
Dezső, L. and Kovács, Á: 1987, in L. Hejna and M. Sobotka (eds.), Proc. 10th European Reg. Meeting of the IAU, Vol. 1, p. 81.
Foukal, P.: 1972, Astrophys. J. 173, 439.
Gesztelyi, L. and Kálmán, B.: 1986, Adv. Space Res. 6, 21.
Gesztelyi, L. and Pap, J.: 1987, in L. Hejna and M. Sobotka (eds.), Proc. 10th European Reg. Meeting of the IAU, Vol. 1, p. 77.
Howard, R.: 1974, Solar Phys. 39, 275.
Howard, R. F.: 1987, in R. Durney and S. Sofia (eds.), The Internal Solar Angular Velocity, D. Reidel Publ. Co., Dordrecht, Holland, p. 23.
Howard, R., Gilman, P. A., and Gilman, P. J.: 1984, Astrophys. J. 283, 374.
Kiepenheurer, K. O.: 1953, in G. P. Kuiper (ed.), The Sun, Univ. Chicago Press, Chicago, Illinois, p. 322.
Maunder, E. W.: 1919, Monthly Notices Roy. Astron. Soc. 79, 451.
Petrovay, K., Brown, J. C., van Driel-Gesztelyi, L., Fletcher, L., Marik, M., and Stewart, G.: 1990, Solar Phys. 127, 51 (forthcoming).
Schröter, E. H.: 1985, Solar Phys. 100, 141.
Sheeley, N. R. Jr.: 1981, in F. Q. Orrall (ed.), Solar Active Regions, Colorado Assoc. Univ. Press, p. 17.
Solar-Geophys. Data Prompt Reports, 1983–1987, Nos. 461–522.
Solar Vector Magnetograms: 1982–1986, Okayama Astrophysical Observatory, Tokyo Astronomical Observatory.
Soln. Dann.: 1983–1987, Nauka, Leningrad.
Spörer, G.: 1879, Publ. Potsdam Obs. 1, Part I.
Ternullo, M., Zappala, R. A., and Zuccarello, F.: 1981, Solar Phys. 74, 111.
Tuominen, J. and Vitanen, H.: 1987, in R. Durney and S. Sofia (eds.), The Internal Solar Angular Velocity, p. 83.
Waldmeier, M.: 1955, Ergebnisse und Probleme der Sonnenforschung, 2nd ed., Geest und Pontig, Leipzig.
Zirin, H.: 1987, Solar Phys. 114, 239.
Zwaan, C: 1981, in S. Jordan (ed.), The Sun as a Star, NASA SP-450, p. 163.
Zwaan, C.: 1985, Solar Phys. 100, 397.
Zwaan, C.: 1987, Ann. Rev. Astron. Astrophys. 25, 83.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Van Driel-Gesztelyi, L., Petrovay, K. Asymmetric flux loops in active regions, I. Sol Phys 126, 285–298 (1990). https://doi.org/10.1007/BF00153051
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00153051