As the Sun Turns: Solar Minimums and Maximums

[Maria]

An update from the Royal Observatory at Belgium

INFO FROM SIDC - RWC BELGIUM 2017 Nov 18 12:30UTC

There are presently 2 numbered sunspot groups on the visible side of the
solar disc, Catania sunspot group 63 (NOAA AR 2687) and group 64 (NOAA AR
2688). Solar flaring activity remains to be low without C-class flares
reported. We expect such a low flaring activity to persist, isolated low
C-class flares are possible but not very probable (probability of only
about 10%). There were no Earth directed CMEs reported, and the solar
protons remained at background level.

The solar wind speed is presently about 410 km/s and the interplanetary
magnetic field magnitude is about 4 nT.

The fast solar wind associated with the large equatorial coronal hole
(reached central meridian in the early morning of November 16) is expected
to arrive at the Earth in the afternoon of November 19.

The arrival of this fast flow might be preceded with the solar wind speed
increase expected to start later today (associated with the low latitude
extension of the southern polar coronal hole which reached central meridian
in the late evening of November 13).

The geomagnetic conditions are presently quiet, we expect unsettled to
active geomagnetic conditions tomorrow due to the arrival of the fast solar
wind.

[Maria]

The Sun Now and the NOAA legacy site posted more than five hours ago show that while AR2687 has significantly decayed to an alpha, active area AR 2688 has now decayed to a plage.

As of now, with no visible sunspot dark cores from either AR2687 or AR2688 on the solar disc, Sunday, November 19, could be declared another spotless day. Yet, as the sun turns, another active area could be just around the corner.

The latest from NOAA is below at 5:30 PM PST (0030 UT):

Joint USAF/NOAA Solar Region Summary
SRS Number 323 Issued at 0030Z on 19 Nov 2017
Report compiled from data received at SWO on 18 Nov
I. Regions with Sunspots. Locations Valid at 18/2400Z
Nmbr Location Lo Area Z LL NN Mag Type
2687 S09E18 175 0030 Hrx 02 04 Alpha
IA. H-alpha Plages without Spots. Locations Valid at 18/2400Z Nov
Nmbr Location Lo
2688 N11W45 238

[Maria]

Sunday, November 19, 2017 is spotless according to Belgium's Royal Observatory.
This means tentatively that we have had 14 spotless days for the month of November.
With 11 more days left in November, we could have even more spotless days.
http://www.sidc.be/products/meu

COMMENT: Both sunspot groups, which were observed on the visible side of
the solar disc during last 24 hours, are decaying. Solar flaring activity
was low and will remain so in the coming hours with very low probability
for C-class flares (about 5%).

There were no Earth directed CMEs observed since last report, and the solar
protons remained at background level.

The Earth is within the slow solar wind (speed of about 360 km/s) and the
interplanetary magnetic field magnitude is very low presently amounting
about 1 nT.

The fast solar wind associated with the large equatorial coronal hole
(reached central meridian in the early morning of November 16) is expected
to arrive at the Earth later today. The geomagnetic conditions are
presently quiet and we expect unsettled to active geomagnetic conditions
starting from this evening, due to the expected arrival of the fast solar
wind.
TODAY'S ESTIMATED ISN: 000, BASED ON 19 STATIONS.

Picture and text below is from http://www.spaceweather.com for November 19, 2017

This is a coronal hole, a region where the sun's magnetic field peels back and allows solar wind to escape. Flowing faster than 600 km/s (1.3 million mph), the emerging gas could cause G1-class geomagnetic storms when it reaches Earth. Arctic sky watchers should be alert for auroras in the nights ahead. Free: Aurora Alerts.

[Maria]

Occasionally, I will see a blocked area on the solar disc image from The Sun Now.

This is a small patch located in the middle of the Southern Hemisphere.
Sometimes the blocked out area takes up one-quarter of the solar disc.

What is happening here?

Is NASA blocking out sensitive data? I am only guessing here.
Could this be a photo of a secret satellite, space station, or
Air Force jet that was accidentally taken by the GOES satellite?

[Maria]

Comments from the Royal Observatory in Belgium:

COMMENT: Over the past 24 hours solar activity has been quiet. No
significant flares have been recorded. All Active Regions (AR) have shown
low levels of activity. No Earth directed Coronal Mass Ejections (CMEs)
have been detected. The greater than 10MeV proton flux remained at
background levels over the past 24 hours. Solar activity is expected to
remain low over the next 24 hours with a low probability of C-class flares.

The solar wind speed has fluctuated between 340 and 370 km/s over the past
24 hours. The total magnetic field strength has fluctuated between 0.7 nT
and 4 nT. The Bz component was largely positive, fluctuating between -1.2
and +3 nT. Geomagnetic conditions ranged between Kp index 0-1 (NOAA) and
local K index 0-2 (Dourbes) over the past 24 hours. A positive polar
coronal hole is currently positioned in the Western hemisphere of the Sun
and the resulting high-speed stream (HSS) may enhance solar wind speeds
later today and as a consequence may increase geo-activity levels.

Geomagnetic conditions are expected to be quiet to unsettled.

TODAY'S ESTIMATED ISN : 000, BASED ON 10 STATIONS.

Concise summary:

Active regions have been reduced to plages and are no longer actively flaring.
Flaring is only at A levels according to GOES X-ray Flux (NOAA).
No sunspot cores. Therefore, the estimated International Sunspot Number is 0.
Solar winds may increase due to the coronal hole, and if so, radio broadcasts
may be interrupted by static.

[Maria]

From the Royal Observatory at Belgium - http://www.sidc.be/index.php

INFO FROM SIDC - RWC BELGIUM 2017 Nov 22 12:30UTC

Over the past 24 hours solar activity has been quiet. No significant flares
have been recorded. All Active Regions (AR) have shown low levels of
activity. No Earth directed Coronal Mass Ejections (CMEs) have been
detected. A small back-sided CME was detected off of the West solar limb,
but is not expected to reach the Earth. The greater than 10MeV proton flux
remained at background levels over the past 24 hours. Solar activity is
expected to remain low over the next 24 hours with a low probability of
C-class flares.

The sun remains spotless.

[Maria]

From NASA -- A huge spiraling magnetic filament is very likely to explode. Any explosion will be geo-centered.

UNUSUAL MAGNETIC FILAMENT: NASA's Solar Dynamics Observatory is monitoring an unusual filament of magnetism on the sun. This image, taken on Nov. 22nd, shows where magnetic forces are holding a massive curl of dense plasma just above the stellar surface:

Magnetic filaments on the sun are not uncommon. Usually they are linear, stretching in only one direction. This one, however, curls back on itself, circumscribing a region more than 280,000 km in diameter. The unusual architecture of the region may undermine its stability. Magnetic fields that criss-cross, like mismatching ends of an incomplete circle, can explode--a process called "magnetic reconnection." Any eruptions this week would likely be Earth-directed.

The scale of this filament makes it an easy target for backyard solar telescopes. Monitoring is encouraged.

http://www.spaceweather.com for November 23, 2017