Abstract
To investigate the differential rotation of sunspot groups using the Greenwich data, we propose an approach based on a statistical analysis of the histograms of particular longitudinal velocities in different latitude intervals. The general statistical velocity distributions for all such intervals are shown to be described by two rather than one normal distribution, so that two fundamental rotation modes exist simultaneously: fast and slow. The differentiality of rotation for the modes is the same: the coefficient at sin2 in Faye’s law is 2.87–2.88 deg/day, while the equatorial rotation rates differ significantly, 0.27 deg/day. On the other hand, an analysis of the longitudinal velocities for the previously revealed two differing populations of sunspot groups has shown that small short-lived groups (SSGs) are associated with the fast rotation mode, while large long-lived groups (LLGs) are associated with both fast and slow modes. The results obtained not only suggest a real physical difference between the two populations of sunspots but also give new empirical data for the development of a dynamo theory, in particular, for the theory of a spatially distributed dynamo.
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References
T. A. Agekyan, Probability Theory for Astronomers and Physicists (Nauka, Moscow, 1974) [in Russian].
O. G. Badalyan, Astron. Rep. 53, 262 (2009).
O. G. Badalyan and J. Sýkora, Contrib. Astron. Observ. SkalnatéPleso 35, 180 (2005).
O. G. Badalyan and J. Sýkora, Adv. Space Res. 38, 906 (2006).
H. Balthasar, M. Schüssler, and H. Woehl, Solar Phys. 76, 21 (1982).
H. Balthasar, M. Vazquez, and H. Woehl, Astron. Astrophys. 155, 87 (1986).
P. A. Gilman and P. V. Foukal, Astrophys. J. 229, 1179 (1979).
V. E. Gmurman, Practical Guide to Solving Problems on Probability Theory and Mathematical Statistics (Vysshaya Shkola, Moscow, 1979) [in Russian].
M. H. Gokhale, Kodaikanal Observ. Bull., Ser. A 2, 217 (1979).
M. H. Gokhale and K. R. Sivaraman, J. Astrophys. Astron. 2, 365 (1981).
M. H. Gokhale and K. M. Hiremath, Astron. Soc. India 12, 398 (1984).
A. A. Grasa, Econometric Model Selection: A New Approach (Kluwer Academic, Dordrecht, Boston, 1989).
K. M. Hiremath, Astron. Astrophys. 386, 674 (2002).
R. Howard, P. I. Gilman, and P. A. Gilman, Astrophys. J. 283, 373 (1984).
J. Javaraiah and M. H. Gokhale, Astron. Astrophys. 327, 795 (1997).
Y. A. Nagovitsyn and A. A. Pevtsov, Astrophys. J. 833, 94 (2016).
Y. A. Nagovitsyn, A. A. Pevtsov, and W. Livingston, Astrophys. J. Lett. 758, L20 (2012).
Y. A. Nagovitsyn, A. A. Pevtsov, A. A. Osipova, A.G. Tlatov, E. V. Miletskii, and E. Yu. Nagovitsyna, Astron. Lett. 42, 703 (2016).
Y. A. Nagovitsyn, A. A. Pevtsov, and A. A. Osipova, Astron. Nachr. 338, 26 (2017).
H.W. Newton and M. L. Nunn, Mon. Not. R. Astron. Soc. 111, 413 (1951).
K. R. Sivaraman, H. Sivaraman, S. S. Gupta, and R. F. Howard, Solar Phys. 214, 65 (2003).
I. Tuominen and H. Virtanen, The Internal Solar Angular Velocity (Reidel, Dordrecht, 1987), p.83.
F. Ward, Astrophys. J. 145, 416 (1966).
R. A. Zappala and F. Zuccarello, Astron. Astrophys. 242, 480 (1991).
F. Zuccarello, Astron. Astrophys. 272, 587 (1993).
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Original Russian Text © Yu.A. Nagovitsyn, A.A. Pevtsov, A.A. Osipova, 2018, published in Pis’ma v Astronomicheskii Zhurnal, 2018, Vol. 44, No. 3, pp. 229–238.
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Nagovitsyn, Y.A., Pevtsov, A.A. & Osipova, A.A. Two Populations of Sunspots: Differential Rotation. Astron. Lett. 44, 202–211 (2018). https://doi.org/10.1134/S1063773718020056
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DOI: https://doi.org/10.1134/S1063773718020056