Solar Rotation Nos: 2241 to 2242
A small rise in sunspot activity comprising mainly short-lived small sunspots and difficult to see solar pores.
Here are the solar highlights for March 2021 together with a selection of images.
Sunspots
AR2804 was still just visible from the previous month but was nearing the solar west limb on the 1st and was not seen on the 2nd leaving the Sun spotless on that day.
AR2806 appeared near the centre of the solar disc on the 3rd at high southern latitude -31°. It was initially type Bxo but seemed to develop on the 4th before decaying to a single pore on the 6th. It seemed to re-develop from the 7th but was at the west limb by the 9th.
AR2807 also appeared on the 3rd but on the eastern hemisphere and at latitude -17°. This too was type Bxo initially and seemed to develop on the 4th before starting to fade away thereafter. It was last seen on the 10th nearing the west limb.
AR2808 came over the east limb on the 9th at +19° as a single sunspot with signs of a light bridge. While at first quite active, it seems to have decayed to two pores by the 15th.
AR2809 sprang into view near the centre of the solar disc at -21° on the 12th type Bxo. It was not seen after the 17th.
AR2810 came over the east limb on the 17th and at +17° it was the second northern hemisphere sunspot this month. It was not seen after the 21st.
AR2811 came over the eastern limb on the 22nd at latitude +21° (type Bxo) as did AR2812 the following day (and at the same northern latitude, but type Hsx). Both were fairly quiet in nature. AR2811 had disappeared by the 28th while AR2812 not seen on the 31st leaving the Sun spotless.
SPA Sunspot Mean Daily Frequency: 0.73 (was 0.60)
SPA Relative Sunspot Number: 9.99 (was 8.57)
Solar Prominences, Plage, Filaments and Flares
Quite a rise in prominence activity but I think it fair to say that most of the prominences seen this month were small and low-lying in nature with a few exceptions.
The 1st saw many small prominences particularly along the west limb, but in contrast on the 7th a grouping of tall prominences appeared on the east limb and a dense looking hedgerow-type prominence appeared on the northeast limb on the 16th turning into a tall intricate prominence on the 17th.
A tall cloud-like prominence appeared on the north west limb on the 30th and a separate prominence was visible on the south limb of the Sun on the 31st.
Filaments were seen on many days, some appearing in small clusters. A conspicuous bowed-looking filament was visible from the 1st to the 3rd near the north limb. Filaproms (both filament and prominence seen at the solar disc edge – or ‘limb’) were seen on the south limb on the 3rd and on the 7th on the west limb.
Bright areas of plage were seen around all the Active Regions as they crossed the solar disc, but there were too some isolated areas of bright plage (unaccompanied by sunspots) that came and went throughout the month.
SPA Prominence Mean Daily Frequency: 3.81 (was 2.03)
Congratulations to Brian Gordon-States who achieved 28 days observed this month, also to Alan Heath and Jonathan Shanklin who achieved 23 days and to Simon Brown on 21 days.
Detailed count records of Active Regions and Relative Sunspot Numbers came from: Simon Brown, Michael Fullerton, Brian Gordon-States, Ian Lee, Lee Macdonald, Jonathan Shanklin, Brendan Shaw and Bob Steele.
Images and drawings were supplied by: Carl Bowron, Mark Beveridge, Ian Lee and Cliff Meredith.
Geoff Elston