Solar activity of the dominant region AR 4493: duration and flares frequency
ATel #17918; Costantino Sigismondi (ICRANet Pescara and UPRA Roma, Italy)
on 21 Jul 2026; 14:09 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Costantino Sigismondi (sigismondi@icra.it)
Subjects: Radio, Optical, Ultra-Violet, X-ray, The Sun, Transient
The active region AR 4493 emerged on 20 July 2026 near the solar center as a Beta-Gamma-Delta region of 120 MH (millionths of solar hemisphere), and on 21 July its area is more than doubled reaching 280 MH;
the rapidity of its growth corresponded to a C-flaring activity, with an high flaring frequency around one per hour in the first day of activity. Three of the flares already peaked to M-class (M2.1-M1.1-M3.4). See the accompanying images (https://drive.google.com/file/d/1Oj_cDvDmD72rMOxxKcOLOYMwEyCxHhCi/view?usp=sharing ).
The Earthside solar X-rays activity in the last day has been produced only by the AR 4493, this is a condition to consider the active region as dominant.
As the previous dominating regions in 2026: AR 4479 (ATel#17879), AR 4473 (ATel#17852, ATel#17851), AR 4419 (ATel#17763) and AR 4366 (ATel#17644), AR4493 can show a three-days intense activity before stopping flaring. Its position at the solar center allows to be geometrically visible for nearly another week, leading possible to monitor from Earth-based Observatories its activity lifetime.
After 1 year (for AR 4274 in November 2025 see ATel #17494) to 1.5 years from the nominal peak of the XXV solar cycle (2019-2023) occurred in October 2024, the activity lifetime of a dominating region has been always limited to 3 days.
For reference the strongest superactive region AR 3664-AR3697-AR3723 survived for nearly three solar rotations (30 times more: 94 days and 969 flares as seen from GOES and Solar Orbiter, Kontogiannis, et al. 2025), flaring for two rotations at X-class level.
The three days time-limit of flaring activity of a dominant active region (nearly one per rotation) might be a characteristic of the present solar cycle, at the descending phase.
AR 4493: frequence and intensity of flaring on 20-21 July 2026
