Popular Astronomy

Share to Facebook Share to Twitter Stumble It More...

Solar Highlights for June 15

Solar Rotation Nos: 2164 to 2165

A fairly quiet Sun currently but as ever there were a few surprises in store for us. Here are the highlights for June 2015 together with a small selection of images.

SUNSPOT SUMMARY

We had a quiet start to the month with sunspot Active Regions (AR)2356 and AR2358 being the most prominent from the 1st to the 3rd. By this time two small groups AR2360 had also come over the (E)ast limb and there was a minor solar flare in this group on the 4th.

More small sunspots had appeared over the E limb by the 5th, designated AR2361 and AR2362. This meant that from the 6th to the 8th the Sun was peppered with small spots especially eastwards of the Central Meridian (CM). It was at this time that our members recorded the highest number of daily sunspot groups (6). AR2360 had by the 8th a few more spots as it passed over the CM. For a while it seemed likely that due the unstable magnetic field, this sunspot would produce solar flares but in the end there were none.

AR2360 was still active as it neared the W limb on the 12th. AR2364 produced a small solar flare on the 10th creating a Coronal Mass Ejection (CME). There was speculation that the CME would lead to aurora at high geographical latitudes but it did not materialise. A second flare active sunspot group (AR2367) had appeared over the E limb by the 12th. This gave us two interesting and active sunspot groups near the E and W limbs right up until about the 15th.

By the 17th AR2367 was nearly at the CM and was still active. AR2371 had appeared over the E limb as well and this developed at a fair pace over the following days to the extent that it was seen with the protected naked eye from the 19th to the 24th. Paradoxically, we saw the lowest daily sunspot count (1) in this period! AR2371 produced a number of flares as it crossed the CM on the longest day of the year and aurora was seen at high geographical latitudes on the 23rd. There were further solar flares on the 25th from AR2371, which was at that time nearing the W limb. In the last few days of June, AR2371 was seen approaching the W limb and finally disappeared over it on the 29th. On the 30th more sunspot activity was seen building-up on the E limb.    

SPA Sunspot Mean Daily Frequency (MDF): 3.36  
SPA Relative Sunspot Number: 51.33

PROMINENCES, PLAGE, FILAMENT AND FLARE ACTIVITY


The 1st saw several intricate prominences on the E and W limbs. Meanwhile, on the solar disk some small filaments were visible and plages were seen concentrated mainly around sunspot group AR2356. The prominences persisted until about the 3rd and thereafter those seen were mainly small or low-lying in nature.

From the 4th onwards there was more activity seen on the solar disk in the form of some limited filament activity but a lot more in the way of plages centred mainly around sunspots AR2356, AR2360, AR2361 and AR2362.

The 11th saw much filament and plage activity stretching away from the E limb and onto the disk particularly around AR2361 and AR2362, AR2365 and AR2366. There were a few prominences, the largest was seen on the E limb. We saw a similar arrangement on the 12th except that there were some new prominences on the NW limb and AR2367 was embedded in plage activity over at the SE limb.

By the 14th AR2367 was further away from the limb but still had a lot of plage activity around it. Across the disk were several filaments and some isolated plage activity near the NW limb. Near AR2367 on the SE limb was a tall hedgerow-type prominence. A similar picture was seen the following day.

Towards the latter half of the month as AR2371 was crossing the solar disk, some plage activity was seen around it but filaments and prominences were again of limited extent. The 22nd and 24th saw some interesting prominence shapes! On the 27th there was extensive, but low-lying, prominence activity along the SE limb some filaments were seen and plages were again seen clustered around AR2371 as it neared the limb.

On the last day of the month, a great deal of prominence, filament and plage activity was seen concentrated along and near the SE limb.

SPA Prominence Mean Daily Frequency (MDF): 5.31  

SOLAR FLARES:

These flares were observed by Alan Heath:


11th     0835UT    Flare on the following (E) limb
           0930UT    Flare still there. Another has appeared centre of disk.
           1030UT    Original flare still visible. Central flare weaker. Another flare has appeared on W limb.
           1100UT    All gone.
16th    0940UT    Flare seen near limb.
21st    0930UT    Flare.
           1030UT    Flare now looks like a plage.
   
Well done to Brian Gordon-States who observed every day in June and to Alan Heath and Jonathan Shanklin who both made observations on 28 days. 

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

Images and drawings were supplied by: Richard Bailey, Mark Beveridge, Carl Bowron, Paul Brierley, John Chapman-Smith, Michael Fullerton, Mick Jenkins, Ian Lee, Peter Paice, Cliff Meredith, Julia Wilkinson and Brian Woosnam.

Geoff Elston

Solar Section Director

Added by: