Izvorni znanstveni članak
An analysis of the solar differential rotation from the Kanzelhoehe sunspot drawings
Ivana Poljančić-Beljan
; Odjel za fiziku, Sveučilište u rijeci
Rajka Jurdana-Šepić
; Odjel za fiziku, Sveučilište u rijeci
M. Čargonja
; Odjel za fiziku, Sveučilište u rijeci
Roman Brajša
; Opservatorij Hvar, Geodetski fakultet Sveučilišta u Zagrebu
Damir Hržina
; Zvjezdarnica Zagreb
Werner Poetzi
; Kanzelhoehe Solar Observatory
Arnold Hanslmeier
; Institute of Physics, IGAM, University of Graz
Sažetak
We present here the results of the behaviour of the solar differential rotation during solar cycles no. 20 and no. 22, derived from Kanzelhoehe sunspot drawings (Kanzelhoehe Observatory for Solar and Environmental Research, University of Graz, Austria).
The positions of sunspot groups were determined using a special software Sungrabber. Sunspot groups were identified with the help of the Greenwich Photoheliographic Results (GPR) and Debrecen Photoheliographic Data (DPD) databases, covering solar cycles no. 20 and no. 22, respectively. In order to calculate the sidereal angular rotation rate ω and subsequently solar rotation parameters A and B we used two procedures: a) daily motion of sunspot groups and b) linear least-square fit from the function CMD(t) for each tracer, where CMD denotes the Central Meridian Distance.
The sample was limited to ±58º in CMD in order to avoid solar limb effects. We mainly investigated velocity patterns depending on the solar cycle phase and latitude.
Ključne riječi
Hrčak ID:
142721
URI
Datum izdavanja:
22.12.2014.
Posjeta: 853 *