TY - JOUR T1 - Time-dependent properties of sunspot groups. I. Lifetime and asymmetric evolution JO - Astronomy and Astrophysics PY - 2021/09/01 AU - Forgács-Dajka E AU - Dobos L AU - Ballai I ED - DO - DOI: 10.1051/0004-6361/202140731 PB - EDP Sciences VL - 653 Y2 - 2025/11/25 ER -