Abstract
We present a comparative analysis of the size of spots in sunspot groups. For the analysis, we have used the characteristics of individual sunspots and pores according to the daily synoptic observations of the Kislovodsk Mountain astronomical station in Solar Cycle 24. We have constructed the distribution of area for the different types of the spots: pores, transitional sunspots, regular sunspots, and sunspots umbrae. We have found that the properties of the sunspots with largest area \([S_{ \mathrm{max}}]\) differ from the other spots \([S_{\mathrm{nomax}}]\) in sunspot groups. In the distribution of area for \(S_{ \mathrm{max}}\) there are two local maxima \(S^{\mathrm{mx}}_{ 1}\approx 10~\mbox{msh}\) and \(S^{\mathrm{mx}}_{\mathrm{2}}\approx130\,\mbox{--}\,180~\mbox{msh}\). The \(S^{\mathrm{mx}}_{1}\) is connected with the transitional spots where the penumbra is not fully developed. For sunspots with \(S_{\mathrm{max}}\) where a penumbra is formed or the ratio \(S_{\mathrm{sp}}/S_{\mathrm{um}}> 3.5\), the maximum \(S^{\mathrm{mx}} _{2}\) corresponds to the diameter of a round spot with \(d \approx25~\mbox{Mm}\). This size is close to the size of the supergranules. In the distribution of area, the two-vertex character is absent for sunspots in the groups with the exception of the spot having the largest area. For developed sunspots with \(S_{\mathrm{max}}\), in the distribution of area of the sunspot’s umbra we have a maximum \(S^{\mathrm{mx}}_{\mathrm{um}} \approx25~\mbox{msh}\). Thus, the two-vertex nature of the distribution of area is a consequence of the existence of pores and sunspots with developing penumbra.
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We acknowledge the financial support Russian Foundation for Basic Research (RFBR, project 18-02-00098) and the Russian Science Foundation (RSF, project 15-12-20001). The author thanks the reviewer for improvement of style and language of this article.
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Tlatov, A., Riehokainen, A. & Tlatova, K. The Characteristic Sizes of the Sunspots and Pores in Solar Cycle 24. Sol Phys 294, 45 (2019). https://doi.org/10.1007/s11207-019-1439-1
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DOI: https://doi.org/10.1007/s11207-019-1439-1