SSTrack: An Automatic Sunspot Identification and Tracking Algorithm to Support the Measurement of Sunspot Rotation

Area of Science:

• Solar Physics
• Astrophysics
• Space Weather

Background:

• Sunspot motions deform the coronal magnetic field, storing energy released during solar flares.
• Sunspot rotation contributes to energy buildup in active regions, potentially triggering eruptive solar events.

Purpose of the Study:

• To develop a fully automatic method for identifying and tracking sunspots.
• To enable large, unbiased statistical surveys of sunspot dynamics and their relationship to solar activity.

Main Methods:

• Development of the automatic sunspot identification and tracking method, SSTrack.
• Testing SSTrack on a four-month dataset previously analyzed with a semi-automatic tool.
• Calculating sunspot rotation about umbral centers using tracking data.

Main Results:

• SSTrack identified 54 of 56 sunspots from the previous sample and 43 additional ones.
• SSTrack identified and tracked sunspots earlier and for longer durations than the semi-automatic method.
• Both methods showed good agreement in rotation calculations for overlapping observations, though fragmentation affected the semi-automatic method.

Conclusions:

• SSTrack is an efficient tool for large-scale statistical analysis of sunspot dynamics.
• The method can capture fine-scale behaviors like sunspot splitting and mergers.
• Accurate tracking is crucial for understanding the relationship between sunspot rotation and solar eruptive events.