Faint partial halo coronal mass ejection

Sunday, 12 May 2019 18:18 UTC

This isn't the first earth-directed coronal mass ejection from sunspot region 2740 but unlike the previous coronal mass ejection this event from 11 May is not a full halo event. This plasma cloud is a partial halo coronal mass ejection that covers about or just over 180 degrees on the SOHO/LASCO C2 coronagraph as you can see on the animation below if you look closely. This combined with the fact that sunspot region 2740 was facing Earth at the time of the eruption does mean that this cloud has a good chance of arriving at Earth. Coronagraph images from STEREO Ahead (header image) confirms this coronal mass ejection comes from the Sun's earth-facing side.

Animation: A faint partial halo coronal mass ejection as seen by the SOHO/LASCO C2 coronagraph instrument.

The speed of this coronal mass ejection is really low estimated to be around the 350km/s which is about the speed of the ambient solar wind. This gives us a possible arrival time for this event somewhere during the second half of 15 May which would be this Wednesday. Geomagnetic storming is unlikely for this event but it is again an event worth keeping an eye on for high latitude sky watchers with dark skies.