NOAA 2192: The sequel
posted: November 26, 2014

With only one more month to go in 2014, huge NOAA 2192 is very probably going to be *the* sunspot group of the year. After its impressive performance just a few weeks ago (see this news item), observers and forecasters were counting down to its re-appearance at the solar east limb. NOAA 2192 obliged by starting its encore performance on 12 November, getting itself a new name: NOAA 2209. Unfortunately, as is sometimes the case with sequels of blockbusters, this group did not live up to the expectations.



To begin with, NOAA 2209's outlook was much less spectacular. Its sunspot area was hardly one third of that of its illustrious predecessor (see graph above, and Note 1). Basically, only the leading and trailing portion were remaining, with hardly any sunspots in between. The group had grown in length, but significantly lost in sunspot area. The difference can also be seen in the pencil drawing underneath made by Jef De Wit from the Belgian Solar Section .


The trailing portion was the largest spot of the group, and many observers mentioned it looked like a bear claw. "Papa Bear" was still visible to the naked eye (using eclipse glasses). Quite a few attendees of last week's ESWW11 took the opportunity to observe the group up close and personal.


The bear claw was magnetically still complex, with a persistent delta spot. Unfortunately, except for a brief hiccup on 15-16 November when it produced 3 M-class flares, nothing spectacular happened. Compared to NOAA 2192, NOAA 2209 produced only half of the number of C flares, a fraction of the number of strong flares, and no X-class flares - as can be seen from graph underneath.



It would be no surprize if NOAA 2192/2209 would survive another farside transit. However, expectations are that by then it will be even smaller and less active. Nonetheless, it may still be worthwhile to get yourself a front-row seat ticket for another sequel of this smash hit.

Note 1 - MH: Millionths of a solar hemisphere, with 1 MH corresponding to about 3 million km2. The total area of the Earth corresponds to about 167 MH, which is a good reference when comparing big sunspot groups.

Credits - Data and imagery were taken from SDO, NOAA/SWPC, NASA/MSFC, and SolarMonitor.