Sunspot AR 4405

Sunspot AR 4405 is a moderate-sized, magnetically simple active region currently visible on the Sun’s surface. It contains 1 visible spot and spans an area of 100 millionths of the solar hemisphere. This region has produced 1 M-class flare, 1 X-class flare so far and currently shows a 0% probability of C-class, 0% of M-class, and 0% of X-class flares. It is located at heliographic latitude S28°, Earth-facing longitude -99°, and Carrington longitude 174°.

Sunspot Location on Map

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Selected map type: AIA 171 Å

Sunspot Properties

Region Number	4405
First Observed	2026-03-26 23:00
Sunspot Type	Hsx
Magnetic Class	A
Area	100 MSH
Number of Spots	1
Extent	17 heliographic degrees
Latitude	-28°
Longitude	-99°
Carrington Longitude	174
Status	d

Flare Activity

Flare Class	Begin Time (UTC)	Peak Time (UTC)	End Time (UTC)	Location	Duration
X1.4	2026-03-29 17:47	2026-03-29 18:19	2026-03-29 18:44	S27E45	32 minutes
M1.3	2026-03-27 17:16	2026-03-27 19:18	2026-03-27 20:35	S24E70	122 minutes

Sunspot Evolution

The following graphs show how this sunspot region 4405 has changed over time. The first graph displays its total area on the solar surface, while the second shows the number of individual sunspots observed within the region.

Sunspot Area

This graph illustrates the physical growth of the sunspot region, measured in millionths of the solar hemisphere (MSH). Increases in area typically indicate developing magnetic complexity and potential for solar activity.

Spot Count

This graph shows the number of visible sunspots within the region at each observation time. A higher spot count often corresponds with a more active or complex region.

Detailed History

Date	Area (MSH)	Spot Count	Classification	Flares	Location
2026-04-09	100	1	Hsx	-	S28W99
2026-04-08	100	1	Hsx	-	S28W85
2026-04-07	120	3	Cso	-	S28W72
2026-04-06	120	4	Eso	-	S28W60
2026-04-05	150	10	Eao	-	S28W46
2026-04-04	200	10	Fao	-	S28W33
2026-04-03	180	12	Eao	-	S27W20
2026-04-02	220	15	Eai	-	S27W07
2026-04-01	210	11	Eac	-	S27E05
2026-03-31	200	11	Esi	-	S27E18
2026-03-30	170	11	Eao	X1.4, 17:47-18:44	S27E32
2026-03-29	180	8	Eao	-	S27E44
2026-03-28	330	8	Ehi	X1.4, 17:47-18:44	S26E55
2026-03-27	270	9	Eho	-	S25E66

Acknowledgements

We gratefully thank the teams behind the Solar Dynamics Observatory (SDO), including the HMI, AIA, and EVE instrument teams, for their continuous work in solar monitoring.

We also thank the National Aeronautics and Space Administration (NASA), the Goddard Space Flight Center (GSFC), and the National Oceanic and Atmospheric Administration (NOAA) for their contributions to solar science and public data access.

Additional event data is provided by NASA’s DONKI (Database of Notifications, Knowledge, Information), which offers alerts and detailed records of solar flares, CMEs, and geomagnetic storms.

Observation Settings