Study of the decay rates of the umbral area of sunspot groups by using a high resolution database

Abstract

The emergence and decay of the sunspot groups are important components of the solar dynamo models. There are two different types of studies on the evolution of active regions. One of them is based on fewer data with higher spatial resolution, the other one uses more data with lower spatial resolution. The input data of the present study allow the investigation with high-resolution both spatially and temporally. The temporal resolution of the SoHO Debrecen Sunspot Database (SDD) is one and a half hours, and it also makes possible to identify all individual sunspots with the position, area, and magnetic polarity. More than 200 sunspot groups have been selected, which have clear maxima on the solar disc, and the decrease of their umbral area is observable during at least four days. The decay rates were calculated by using two data: the umbral area and the number of contained sunspots -- these decay rates were computed for the total umbral area of sunspot groups and their leading and following parts. The decay rate has a linear area dependency, and it is higher for the following part than for the leading one.

arXiv comment10 pages, 8 figures, accepted for publication in the ApJ

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Cited by in corpus (5)

• On the Decay of Sunspot Groups and Their Internal Parts in Detail
• On the size distribution of spots within sunspot groups
• The Decay of Two Adjacent Sunspots Associated with Moving Magnetic Features
• Variation of sunspot groups' polarity separation during their evolution
• The Decay Process of an α-configuration Sunspot