Sol Gets a numbered sunspot

Near-Live image of the sun in 304 angstrom as seen by NASA’s SDO.

It has been a surprise in the last 12 months to see a numbered sunspot on the face of Sol, but we have one today in NOAA Active Region 2575 (Catania sunspot group 28). The sunspot is stable but inactive. This image is for that part of teh spectrum centred on 304 Angstroms where photons are emitted by Helium 2 at around 50,000C, in the chromosphere and the transition region. Solar activity is expected to remain low with a low probability of flares or mass ejections.

In the past 24 hours the solar wind speed remained slightly enhanced under the influence of a negative polarity coronal hole and increased from around 400 to 520 km/s. The total interplanetary magnetic field strength was in the range of within 5-8nT in the beginning of the period and has decreased to below 3nT at 12 UTC today. The Bz component was mostly negative with a minimum value of -7 nT. The solar wind conditions are expected to remain enhanced over the next 24 hours.

Sunspots on the face of our star remain few in number as we are in the middle of the solar minimum. Solar Cycle 25 will be the 25th Solar Cycle since 1755. Solar cycles are marked by a reversal in magnetic polarity, with the first convincingly reversed sunspots of SC 25 occuring in November 2019. SC 25 solar maximum should occur between 2023 and 2026 with 2031 seeing the end of the cycle. The strength of SC 25 is debated with predictions of 30-50% of SC24 to somewhat stronger than SC24.

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