Letter Re: New Large Sunspots Generating X Class Solar Flares


[ Sunspot] 11515 started out squirrely, was and remains same.

The X-output has actually started to resume a slightly more regular decay at this point, not completely but still at least a change in the right direction. I was actually typing a brief update on the “Fading” 11515 and the newly enumerated 11520 ( old 11504) after the M-6.9 earlier when the output rose, fell back, and then rose again. THIS is not the behaviour we’d be expecting just after the previous flare. We would be expecting a precipitous drop  (a spike type) or alternately a long steady, concave-up decay were the flare of the LDE type but this, no. The post-flare levels are at around C-5.5 though with each iterative 1min update additional decay is visible. As to the specifics, the full spectrum of flare warnings were generated at NOAA by this; Types, II, IV and tenflare, see the attached text for further specific details.  Though I can’t seem to find where I just filed it, NOAA also reported a very high plane-of-sky emission speed for this event, when I find it I’ll pass it along.

NOAA has gotten around to re-enumerating old 11504 as stated so at least we have a valid current reference.

NOAA 11520 is very large, NOAA only list the area as 510 SM whilst Solen gives a 1500 figure. I’m still not sure where the endless discrepancy between these two arises from but NOAA gave a figure for 11515 of 780 SM at the most recent update at about 00:30 this morning and 11520 is much larger by any objective measure. Thankfully, 11520 has been relatively quiet producing as yet only a low M-class event more than 24 hours ago. This is not to say that it should be ignored; A very large negative polarity region central to the spot is boiling with magnetic potential. That potential is confirmed by examining the HMID Doppler which clearly shows significant, large  magnitude “feathering” in that region in the images. Wow, is this the month for weirdness or what? Oops, the NOAA graph is tipping up again, more later as warranted. – J.E.B. in Missouri