Solar Rotation Nos: 2231 to 2233
This summary covers two months.
We saw more of the New Solar Cycle (No.25) sunspots in this period than we have seen before. There was a slight rise in sunspot activity but the Sun is still in a deep Solar Minimum.
Here are the solar highlights for June and July 2020 together with a selection of images.
Sunspots (June)
AR2764 was a Solar Cycle 25 sunspot and came over the NE limb on the last day of May and was still visible as a tiny Axx type sunspot at latitude +35° in early June. It is unsure whether AR2764 disappeared on the 1st or this tiny sunspot was simply overlooked, however, it was back with us on the 2nd, but only for a single day as the Sun appeared spotless on the 3rd.
AR2765 appeared over the east limb on the 4th as another small Hsx type sunspot at a high southern latitude of -24° making it another Cycle 25 spot. Unlike many recent sunspots, AR2765 showed a distinct umbra and penumbra. Faculae were seen in this region from the 4th to the 6th. Spaceweather.com announced several minor solar flares on the 7th and 8th. The sunspot survived its passage across the solar disc, with faculae showing again on the 13th as it neared the solar limb, before disappearing over the SW limb on the 16th.
The Sun was then spotless from the 17th until the 30th.
SPA Sunspot Mean Daily Frequency: 0.41 (was 0.01).
SPA Relative Sunspot Number: 5.41 (was 0.10).
Sunspots (July)
The Sun was spotless from the 1st until the 4th.
AR2766 appeared on the 5th and in contrast those seen in June, this Bxo type sunspot was an old Solar Cycle 24 sunspot at the relatively low latitude +6°. However, it decayed rapidly so much so that it had gone by the 7th.
The Sun became spotless again from the 7th to the 21st.
AR2767 came over the east limb on the 22nd and at latitude -22°. This was a fairly typical sunspot (of type Hsx) and appeared fore-shortened while close to the solar limb. AR2767 was quiet despite being a new Solar Cycle sunspot. This was later joined by AR2768 on the 29th as it headed westwards and was still visible by the 31st.
AR2768 was another Cycle 25 sunspot of type Axx and at latitude +25°. It remained visible as we reached the end of the month.
SPA Sunspot Mean Daily Frequency: 0.43 (was 0.41).
SPA Relative Sunspot Number: 4.61 (was 5.41).
Solar Prominences, Plage, Filaments and Flares (June)
Mostly small prominences throughout the month but some were more substantial.
A bright hedgerow prominence was seen on the NW limb on the 1st and 2nd.
A broad darkish isolated filament was seen near the SE limb on the 5th while AR2765 showed extensive bright areas of plage around it. The dark filament, though it changed shape, persisted from the 5th to the 8th while the areas of bright plage remained in one form or another around AR2765 even as it neared the west limb on the 16th. A long dark filament seen extending from AR2765 was christened ‘the Scorpion’s tail’ on Spaceweather.com.
A developing hedgerow prominence appeared on the west limb on the 17th. By the 18th this had become a smoke-stack type prominence. By the 20th a fine arch-type prominence was seen on the west limb. I am unsure if these were all related or three separate prominences.
No solar flares were reported to the Section in this period.
SPA Prominence Mean Daily Frequency: 1.13 (was 2.60).
Solar Prominences, Plage, Filaments and Flares (July)
An extensive prominence was seen on the west limb on the 2nd along with numerous isolated filaments near the north and east limbs.
Dark isolated filaments appeared near the north limb on the 5th and 6th.
A some-stack prominence was seen on the 24th on the SW limb and on the east limb on the 26th.
AR2767 showed bright plage scattered around it on the 23rd. These were seen again, in reduced number, from the 24th onwards and an area of scattered bright plage was seen between new sunspot AR2768 and the SE limb on the 29th. The 29th also saw tall bright prominences along the SE limb. One of these developed into a long thin curved flame-like prominence reaching out from the south limb on the 31st. A very impressive feature!
No solar flares were reported to the Section in this period.
SPA Prominence Mean Daily Frequency: 0.97 (was 1.13).
Congratulations to Brian Gordon-States who observed 30 days in June and 31 days in July. Also to Jonathan Shanklin who observed 27 days in June and 28 days in July and to Michael Fullerton who manged 25 days in June and 26 days in July.
Detailed count records of Active Regions and Relative Sunspot Numbers came from: John Chapman-Smith, Brian Gordon-States, Michael Fullerton, Mick Jenkins, Ian Lee, Lee Macdonald and Bob Steele.
Images and drawings were supplied by: Mark Beveridge, Paul Brierle y, Carl Bowron, Alan Clitherow, Murray Foster, Ian Lee and Cliff Meredith.