M1.1 solar flare from behind the east limb

Saturday, 21 October 2017 08:36 UTC

M1.1 solar flare from behind the east limb

A huge surprise last evening as solar activity unexpectedly reached moderate level thanks to an M1.11 (R1-minor) solar flare that took place behind the east limb. The solar flare peaked at 23:28 UTC on 20 October 2017.

The solar flare was associated with a Type II Radio Emission and a slow coronal mass ejection that of course isn't directed towards our planet. Source of the solar flare seems to be the same area that was responsible for a double eruption back on 18 October. This area used to be the home of sunspot region 2673 two rotations ago (yes that is indeed the sunspot region that produced four X-class solar flares) and sunspot region 2682 during the previous rotation. It looks like this sunspot region is back for a third time and somehow became active again! Exciting! There is only 1 small sunspot visible right now so if there are more spots hiding behind the limb they should become visible in the near future. The SDO website is down at the moment so it's hard to get up to date imagery but we hope they will come back online soon.

Image: SOHO LASCO C2 difference frame showing the M1.1 coronal mass ejection as it is ejected into space. The plasma cloud is not directed towards Earth.

Any mentioned solar flare in this article has a scaling factor applied by the Space Weather Prediction Center (SWPC), the reported solar flares are 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.

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