As the Sun Turns: Solar Minimums and Maximums

[Maria]

solar image_12-11-2017_Are there 2 new active regions.jpg (13.82 KiB) Viewed 1539 times

Tonight we have had a glimpse of what looks like a tiny sunspot near the Western Limb of the sun that is between the rim and the center of the solar disc. In addition, something is also approaching the Western Limb of the sun, but it is too early to tell if there are any dark sunspot cores that are visible.

Click: https://sdo.gsfc.nasa.gov/assets/img/la ... _HMIIF.jpg

Could these be more active regions? Or will they quickly decay into plages?

Stay tuned to As The Sun Turns for more developments during this Solar Minimum, when sunspots are an extraordinary and infrequent event.

[Maria]

This in from NOAA:

Joint USAF/NOAA Solar Region Summary
SRS Number 345 Issued at 0030Z on 11 Dec 2017
Report compiled from data received at SWO on 10 Dec
I. Regions with Sunspots. Locations Valid at 10/2400Z
Nmbr Location Lo Area Z LL NN Mag Type
2691 S03E42 221 0010 Axx 01 01 Alpha

Apparently, this new active region 2691 has produced several B flares
yesterday and today with a B6.2 at 2017-12-11 00:52:00 UTC.

Belgium predicts no higher than C flaring from this same sunspot region.

[Maria]

Newest report from NOAA:

Joint USAF/NOAA Solar Region Summary
SRS Number 346 Issued at 0030Z on 12 Dec 2017
Report compiled from data received at SWO on 11 Dec
I. Regions with Sunspots. Locations Valid at 11/2400Z
Nmbr Location Lo Area Z LL NN Mag Type
2691 S03E29 220 0010 Bxo 01 03 Beta
IA. H-alpha Plages without Spots. Locations Valid at 11/2400Z Dec
Nmbr Location Lo
2690 N06W87 336
II. Regions Due to Return 12 Dec to 14 Dec
Nmbr Lat Lo
2689 N13 130

The little active region, AR 2691, is expanding and has increased from Alpha to Beta.
AR 2689 in the Northern Hemisphere may also be returning from its journey on the far side of the sun.
Thus, we may have two active regions to break the spotlessness of the solar disc.

[Maria]

Comments from Belgium's Royal Observatory

COMMENT: The Sun did not produce any C flares in the past 24 hours. The
chance for a C flare in the next 24 hours is estimated at 15%. No Earth-
directed Coronal Mass Ejections (CMEs) were observed in available
coronagraphic imagery. The greater than 10 MeV proton flux was at nominal
levels.

In the past 24 hours, solar wind speed measured by DSCOVR increased from
420 to 530 km/s, while the magnitude of the Interplanetary Magnetic Field
(IMF) varied between 2 and 15 nT. There were no extended periods with Bz
below -5 nT. These enhanced solar wind conditions are due to the high speed
stream from the positive coronal hole that crossed the central meridian on
December 8. Continued influence from this high speed stream is expected on
December 12 and 13. Quiet to unsettled geomagnetic conditions (K Dourbes
between 1 and 3; NOAA Kp between 1 and 3) were registered in the past 24
hours. Quiet to active geomagnetic levels (K Dourbes < 5) are possible on
December 12 and 13 due to the influence of the high speed stream associated
with a positive coronal hole, with a chance for minor storm conditions (K
Dourbes = 5). Quiet to unsettled geomagnetic levels (K Dourbes < 4) are
expected on December 14.
TODAY'S ESTIMATED ISN : 013, BASED ON 08 STATIONS.

AR2691 appears to be decaying.

[Maria]

solar image_12-13-2017_magnetic filaments on solar rim_0057UT.jpg (217.26 KiB) Viewed 1527 times

Look at all the magnetic filaments that can be seen on the edge of the solar disc!
And approaching the center of the disc is AR2691.

From NOAA: AR2691 seems to have rebounded.
And we may have a new active region within a day or two.

Joint USAF/NOAA Solar Region Summary
SRS Number 347 Issued at 0030Z on 13 Dec 2017
Report compiled from data received at SWO on 12 Dec
I. Regions with Sunspots. Locations Valid at 12/2400Z
Nmbr Location Lo Area Z LL NN Mag Type
2691 S03E16 220 0010 Bxo 04 03 Beta
IA. H-alpha Plages without Spots. Locations Valid at 12/2400Z Dec
Nmbr Location Lo
None
II. Regions Due to Return 13 Dec to 15 Dec
Nmbr Lat Lo
2689 N13 130

[Maria]

A quick glance at The Sun Now shows a spotless sun. Yes, there are plages, but no dark cores.
Here is a shot from NASA: https://sdo.gsfc.nasa.gov/assets/img/la ... _HMIIF.jpg

Belgium's consortium of astronomers also agrees that the sun
again is spotless with AR2691 decaying into a plage.

Will AR2691 become active again?
Will a new sunspot appear from the far side of the sun?
Will one of the solar filaments burst and send an earthbound CME?

Anything could happen. Look at all the filaments on the solar disc!
In the picture below, magnetic filaments are seen as lines.
Look especially at the one near the southwestern limb of the sun.

The very dark spots at the solar poles and elsewhere are coronal
holes from which solar winds are emitted.

Visit us again to see how the sun turns.

[Maria]

Belgium's comments from the Royal Observatory are posted below:
http://www.sidc.be/products/meu/

COMMENT: The Sun did not produce any flares in the past 24 hours. The
chance for a C flare in the next 24 hours is estimated at 5%. No Earth-
directed Coronal Mass Ejections (CMEs) were observed in available
coronagraphic imagery. The greater than 10 MeV proton flux was at nominal
levels.

In the past 24 hours, solar wind speed measured by DSCOVR varied between
about 440 and 540 km/s, with current values around 475 km/s. The magnitude
of the Interplanetary Magnetic Field (IMF) varied between 1 and 9 nT. Bz
was around -5 nT between 15:45 and 17:15 UT on December 12. A high speed
stream from a recurrent positive equatorial coronal hole is expected to
arrive in the second half of December 15 or early on December 16. Quiet to
active geomagnetic conditions (K Dourbes between 1 and 4; NOAA Kp between 1
and 4) were registered in the past 24 hours. The active interval (K Dourbes
= 4) between 18h and 21h UT on December 12 was related to Bz values around
-5 nT. Quiet to active geomagnetic levels (K Dourbes < 5) are possible on
December 13 and 14 and the first half of December 15, with a chance for
minor storm conditions (K Dourbes = 5). Quiet to minor storm conditions (K
Dourbes < 6) are expected in the second half of December 15, with a chance
for moderate geomagnetic storm intervals (K Dourbes = 6), due to the
expected arrival of a high speed stream from a recurrent positive
equatorial coronal hole.

TODAY'S ESTIMATED ISN : 000, BASED ON 12 STATIONS.

The sun is spotless again.
Of 15 stations reporting to Belgium, all 15 stations agree that the EISN is 0.00.
So far, in December, we have had 9 spotless days out of 13.
Last month, in November, we had 19 spotless days.

To see the EISN/SILSO plot of Estimated International Sunspot Numbers,
please visit http://www.sidc.be/silso/eisnplot