Region 12192 Biggest in 2 Solar Cycles (Updated)

Active Region 12192 is the largest region since November 18, 1990, a full two solar cycles ago.  To see what we might expect, we took a look back at the region from 1990 (Region 6368).  At its largest, region 6368 was about 10% larger than region 12192.  During its entire transit across the Earth facing side of the Sun, region 6368 did not produce any R3 or larger Radio Blackouts (X-class flares).  Already, region 12192 has surpassed that region in term of production of significant solar flares.  The full tally, keeping in mind that region 12192 has about 3 more days before rotating to the far side of the sun, is given in the table below.  Remarkably, Region 12192 has yet to produce any radiation storms or significant Earth-directed coronal mass ejections (CMEs).  As this region approaches the limb, the threat of Earth-directed CMEs is in decline.  However, this region is still in a favorable position for production of radiation storms should subsequent eruptions continue. 

 

Comparing two large active regions

	Region 6368 (1990)	Region 12192 (2014)*
R3-R5 (X-class) flares	0	6
R1-R2 (M-class) flares	14	24
(C-class) flares	96	67

*Through mid-day October 28.

 

Image courtesy of the NASA SDO HMI team