The Growth and Decay of Individual Sunspots and Pores

An analysis of the photometric growth and decay rates of sunspots and pores was carried out. According to the Solar Dynamics Observatory/Helioseismic and Magnetic Imager data for the period 2010 May–2025 March, ≈3.5 × 105 sunspots and pores were detected and their evolution tracked. The growth and decay rates of sunspots depend nonmonotonically on the area. For small-area sunspots S ≲ 50 μsh, a rapid increase in velocity is observed with increasing area for the growth stage and for the decay stage μsh day−1. For sunspots S ≳ 50 μsh, the growth rate depends weakly on the area: μsh day−1. For the decay stage of sunspots with an area of S ≈ 50–150 μsh, the decay rate also depends weakly on the area and can be approximated as . For sunspot areas S ≳ 150 μsh, the decay rate accelerates with increasing area: μsh day−1. For solar pores, the growth and decay rates of solar pores are linearly related to the area. The growth and decay rates for the spots of the leading and trailing polarities are determined. In the range of spot areas S ≈ 100–200 μsh, the growth and decay rates of sunspots of trailing polarity are higher than those of sunspots of leading polarity.