A&A 534, A47 (2011) Astronomy DOI: 10.1051/0004-6361/201116790 & c ESO 2011 Astrophysics Statistical properties of superactive regions during solar cycles 19–23 A. Q. Chen1,2,J.X.Wang1,J.W.Li2,J.Feynman3, and J. Zhang1 1 Key Laboratory of Solar Activity of Chinese Academy of Sciences, National Astronomical Observatories, Chinese Academy of Sciences, PR China e-mail:
[email protected];
[email protected] 2 National Center for Space Weather, China Meteorological Administration, PR China 3 Helio research, 5212 Maryland Avenue, La Crescenta, USA Received 26 February 2011 / Accepted 20 August 2011 ABSTRACT Context. Each solar activity cycle is characterized by a small number of superactive regions (SARs) that produce the most violent of space weather events with the greatest disastrous influence on our living environment. Aims. We aim to re-parameterize the SARs and study the latitudinal and longitudinal distributions of SARs. Methods. We select 45 SARs in solar cycles 21–23, according to the following four parameters: 1) the maximum area of sunspot group, 2) the soft X-ray flare index, 3) the 10.7 cm radio peak flux, and 4) the variation in the total solar irradiance. Another 120 SARs given by previous studies of solar cycles 19–23 are also included. The latitudinal and longitudinal distributions of the 165 SARs in both the Carrington frame and the dynamic reference frame during solar cycles 19–23 are studied statistically. Results. Our results indicate that these 45 SARs produced 44% of all the X class X-ray flares during solar cycles 21–23, and that all the SARs are likely to produce a very fast CME.