Sunspots come in all sizes and shapes. Some groups of sunspots have a more complex magnetic structure than other sunspot groups and are more likely to produce solar flares. But how do we know if a sunspot group is a threat for strong solar flares? To know the differences, the Mount Wilson observatory in California (USA) made rules so that every sunspot region receives a certain magnetic classification.
Every single day the sunspots on the Sun are counted and every sunspot group receives a number, a magnetic classification and spot classification by the space weather specialists. On our website you can find an overview of all the sunspot groups together with their classifications. Below you will get to know what all of those mean.
More than half of the observed sunspot groups receive an Alpha or Bèta classification, where bigger sunspots are often more complex and get a Bèta, Bèta-Gamma or Bèta-Gamma-Delta classification. It is well known that delta sunspots can be very active and produce the most intense solar flares.
Let’s dig a bit deeper into the magnetic delta class. This is the most interesting type of sunspot structure due to the high solar activity which they often cause. With the following list you can determine whether a sunspot has a magnetic delta structure:
An example of a very complex sunspot group with a Bèta-Gamma-Delta magnetic classification as seen by NASA SDO’s HMI instrument. This sunspot region was the source of a major X2.3 solar flare. The top image shows us this sunspot region in visible light. The bottom image is a so called ‘’magnetogram’’ and shows the magnetic layout of a sunspot region. The red color indicates sunspots or areas with a negative polarity and the blue color indicates areas with positive polarity sunspots.
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