Friday, 31 August 2012

AR11520: Ghost that Walks!

An impressive prominence at the sun's SE limb on 2012 August 27 suggested a large filament was about to appear. Next day it was very distinct on the disc at the foot of the prominence.  On the 30th it was wholly on the disc - an impressive sight - flanked by tiny spot groups11562 and 563. 'Helio' sited the filament, apparently, right on the old AR11520 site from early July (posts below). Big active region filaments like this can erupt spectacularly.  And it did so as I slept: on Aug 31 22:00 UT an array of bright flare ribbons were strewn across the site (a-a and b-b), as well as a few filaments that had somehow survived the ejection's turmoil. GOES logged a long-lived C8.4 flare at the site with a beautiful flare arcade in SDO AIA EUV images. The old AR11520 site is far from dead yet!

And readers, last night my friends at ASNSW saw fit to grant me the McNiven Award for astronomy : a very proud moment indeed.

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