Asymmetries, tilt-angles, and differential rotation from sunspot observations by H.S. Schwabe

• Antragsteller: Dr. Rainer Arlt
• Fachliche Zuordnung: Astrophysik und Astronomie
• Förderung: Förderung von 2011 bis 2014
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 202226362

Positions and sizes of sunspot groups have been available continuously back to 1874. Extending these data into the past would deliver a more precise picture of the nature of the solar cycle. We propose to extent the positional and area data set by the sunspot observations by H.S. Schwabe from 1825–1867. The observations were digitized by the PI in 2009. The individual positions and areas of the sunspots as well as their groupings in active regions have to be determined for all spots. We propose to determine the solar butterfly diagram from these positions, the north-south asymmetry from them, possible phase shifts of the northern against the southern hemisphere, average tilt angles over the four cycles observed, and sunspot decay leading to turbulent diffusion values in the solar atmosphere. Another goal is also the determination of the differential rotation of the Sun in the 19th century. An extension of the search for possible persistent active longitudes on the Sun will also be possible.

• DFG-Verfahren: Sachbeihilfen