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Solar Highlights for February 16

 

Solar activity increased very slightly in February. We saw mostly small sunspots for much of the time. In contrast, H-alpha activity seems to have been higher with far more to see. Once again the weather impacted on the number of observations received.
  
Here are the highlights for February 2016 together with a selection of images.

SUNSPOT SUMMARY

The Sun was still quiet, a trend that we have seen throughout most of last month and it seemed to be continuing. From the 1st to the 3rd we had three small sunspots visible, the most prominent of these was (A)ctive (R)egion 2489, seen nearing the W limb. By the 4th AR2492 and AR2493 had appeared over the E limb, both small.

It was on the 5th that AR2494 suddenly appeared on the disk. It showed two spots plus some intervening pores and was classed type Dai on that day. As the sunspot group had developed so rapidly it was thought it might also be solar flare active but just as it had appeared suddenly it started to fade rapidly too, so that by the 7th the group leader sunspot had almost gone. The leader spot did reappear again on the 8th but thereafter AR2494 faded from view as it headed westwards towards the solar limb.

Around the 8th AR2497, at that time lying east of the (C)entral (M)eridian, had just like AR2494 had also shown rapid development so that by the 11th it was easily visible near the centre line of the Sun’s disk. This group of many small sunspots was active and a C-class occurred later that day at 2103UT. This later gave rise to a (C)oronal (M)ass (E)jection. AR2497 generated an M-class flare on the 13th. Mick Jenkins reported seeing a C1 solar flare on the 17th as the sunspot group neared the W limb.

We then entered another quiet phase. There were small sunspots on the solar disk, the most prominent was AR2501, a type Cso sunspot, it crossed the CM around the 20th. As AR2501 headed towards the W limb, the Sun showed a few very small sunspots. It was not until the 28th that AR2506 (classed as type Dai that day) which showed rapid development as it crossed the CM.

For more about the sunspot classification, see:
http://www.popastro.com/solar/solarobserving/chapter.php?id_pag=358

SPA Sunspot Mean Daily Frequency (MDF): 2.74 
SPA Relative Sunspot Number: 40.50

PROMINENCES, PLAGE, AND FILAMENTS
   
The SE limb of the Sun had a fine filaprom on the 2nd. This comprised of a high hedgerow type prominence on the limb and a filament extending on to the disk from the southern end of the prominence. There was extensive plage activity seen across the disk as well.

Bright plage activity was seen around sunspots AR2494 and AR2497 on the 10th and 11th.

Another filaprom was seen on the 15th on the SE limb, the prominence there could be seen at the northern end extending onto the disk. Over on the NW limb the filament activity seen preceding AR2497 a day or so earlier was by now showing up as several small prominences on the limb.

Mick Jenkins observed long filament (estimated by him to be around 263,000km long) on the 17th with a “tornado shape” extension reaching up to an estimated height of around 94,000km. The same filament was drawn by Ian Lee on his disk drawing on the 18th.

The 19th saw quite a lot of prominence activity along the W limb and a fairly big smokestack type prominence was seen on the NE limb on the same day.

By the 23rd, as AR2501 and AR2505 were nearing the W limb, several filaments and plage activity was visible across the Sun’s disk but of particular note was a curved filament and plage near to AR2501. The curved filament and plage remained visible and was seen and drawn by Ian Lee again on the 25th. Also visible on the 25th were two detached prominences seen lying above the SE limb.

The 28th saw AR2506 at the CM with associated plage activity around it. Also seen were a hedgerow prominence on the E limb and a smaller but still sizable prominence on the W limb.

SPA Prominence Mean Daily Frequency (MDF): 4.96

Well done to Brian Gordon-States who observed the Sun on 27 days in February. Alan Heath and Jonathan Shanklin observed on 23 days and 21 days respectively.

Detailed count records of Active Regions and Relative Sunspot Numbers came from: Brian Gordon-States, Michael Fullerton, Alan Heath, Mick Jenkins, Ian Lee, Jonathan Shanklin.

Images and drawings were supplied by: Mark Beveridge, Carl Bowron, Paul Brierley, Mick Jenkins, Ian Lee, Cliff Meredith, Brian Woosnam and Julia Wilkinson.


Geoff Elston

Director

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