Backside eruptions

Once again, solar observers were treated on a blemishless golden orb, with the preliminary sunspot number being "0" from 25 June onwards. While the earth-facing solar hemisphere had apparently already left for the summer holidays, the Sun's backside still showed some signs of life, displaying a few active regions.

Impressive eruption

No C-class or stronger flares, and several spotless days: Last week will not be remembered for its high solar activity. Fortunately, some spotless active regions were rounding the east solar limb

A long duration geomagnetic storm

Early May, one small and one large coronal hole transited the solar disk's centre. As expected, the associated high speed streams arrived at Earth just a few days later.

Spotless days

The already very low solar activity of the last few months ended into a downright traumatic experience for the solar observers when, starting on 3 June, the Sun became totally devoid of its so familiar speckles. Indeed, from 3 till 7 June, no sunspots were observed, and the daily estimated sunspot number was at comatose levels (flat "0") for 5 consecutive days. The gif underneath shows SDO/HMI imagery of the solar disk from 1 till 8 June.

Quiet week, lovely events

Solar flaring activity was once again restricted to a handful of minor C-class flares this week. A few regions drew away all attention: Departing NOAA 2546, emerging NOAA 2548, and ...

An early application...

We are still far from the year's end, yet we already received an application for the most impressive solar event of the year. A relatively modest C3 flare ...

One year with no X-class flares

X-class flares are "eXtreme" x-ray solar events, 10 times more powerful than a "medium" M-class flare, and 100 times more powerful than the "common" C-class flares.

NOAA 2529 remains active

The big sunspot group NOAA 2529 was a relatively quiet region before producing an M6 flare early on 18 April. The coronal mass ejection (CME) associated with this "medium" flare was not directed to Earth.

Dynamic NOAA 2529

Over the last two weeks, the Sun's outlook has been dominated by the big active region NOAA 2529. This sunspot group was relatively quiet, producing only a handful of low-level C-class flares... before erupting in a strong M6 flare early on 18 April. Despite being quiet most of the time, close examination of the available imagery showed important dynamics in the region, in particular the main spot. Note that at its maximum size, the main spot had a diameter of almost 5 times that of the Earth, and its total surface area was over 5 times that of our planet.

Comin' around the bend

Solar activity has been very low over the last weeks, with very few or no C-class flares at all. The x-ray background flux was also low, at or just below the B1 level. Around noon on 5 April, this background flux started a gentle increase to values slightly above B3 on 7 April, coinciding with the appearance of a big sunspot near the solar east limb.



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