Sun

Sun activity: Bam! X Flare!

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More sun activity! An X-flare blasted from sunspot AR2994, on the northeast limb of the sun (left side of sun in this image), the part just rotating into view, on April 17, 2022. Image via LASCO.

April 17: X-flare!

Newcomer sunspot region AR2994 blasted out an X-flare at 3:34 UTC this morning (April 17, 2022). Before the blast, we saw a very active northeast limb (edge) of the sun. There seemed to be action on the sun’s far side, too. And now the sun’s rotation has carried some of that action into view. The old sunspot regions AR2975 and AR2976 – last seen some days back before the sun’s rotation carried them out of view – have merged. The newly arrived sunspots are labeled AR2993 and AR2994. Plus, there is one more sunspot in this region, barely showing. All this is happening on the sun’s northeast limb.

A busy week is anticipated with C- and M-class flares and possibly even more X-flares.Stay tuned!

The sun, seen as a large yellow sphere with small dark spots.
Today’s sun (3 UTC on April 18, 2022). Image via NASA SDO. View this image with labels, via SpaceWeather.com. Today’s sun is posted by Armando Caussade

April 16: Sun activity picking up

The sun was busy with multiple flares – between C- and M-class – on Friday and again so far this morning (April 16, 2022)! Most activity had been on the far side, the side we’re currently not seeing from Earth. You can see a classic “lightbulb” shape in a (non-Earth-directed) CME released from one of the flares on the sun’s limb. See the video in Alex’s tweet, below.

A primary flare source appears to be the old sunspot AR2975. There’s lots of chatter online about this region, and about what it’ll be re-named when it comes fully into view, probably around April 17. The sun rotates approximately once every 27 days. So the same sunspots might come into view on the Earth-facing side again and again. Each time, they get a new label.

Yellow and purple lines with arrows pointing at the peaks.
April 16, 2022, GOES X-Ray Flux chart showing peaks on northeast limb. Active sun in the far side close to the edge. A couple of these peaks reached M class. Via NOAA GOES.
Blue wave coming from the sun.
Sun flare on the southeast limb of the sun on April 15, 2022. Sunspot AR2975, now on the sun’s far side, will rotate into view in the coming week. Image via NOAA.

April 14: G2 geomagnetic storm is here

A G2 geomagnetic storm – a moderate storm – is ongoing. The Earth-directed CME from the beautiful filament eruption on April 11, 2022, has arrived. By midday on April 14 (according to clocks in North America), the Kp index – which describes the disturbance to Earth’s magnetic field by the solar wind – reached 5 (mild) and may rise to 6 (moderate). Be on the alert for auroras in the next few days. Latitudes like those in the northern United States might see auroras.

According to NOAA’s Space Weather Scales, during a G2-class storm:

Power systems: High-latitude power systems may experience voltage alarms, long-duration storms may cause transformer damage.
Spacecraft operations: Corrective actions to orientation may be required by ground control; possible changes in drag affect orbit predictions.
Other systems: HF radio propagation can fade at higher latitudes, and aurora has been seen as low as New York and Idaho (typically 55 degrees geomagnetic latitude.).

Map of North America with wide green band in northern part.
Aurora forecast for North America – April 14, 2022 – from the University of Alaska. Weather permitting, highly active auroras may appear overhead from Inuvik, Yellowknife, Rankin and Iqaluit to Vancouver, Helena, Minneapolis, Milwaukee, Bay City, Toronto, Montpelier, and Charlottetown, and be visible low on the horizon from Salem, Boise, Cheyenne, Lincoln, Indianapolis and Annapolis. Image via University of Alaska.

April 14: The sun over the past week

April 12: Yesterday’s S-shaped filament eruption

Yesterday, the old sunspot group AR2987 produced an eruptive C1-class solar flare, and more is known about it now. Observers had thought this region was inactive. Spaceweather.com therefore called it the corpse of an old sunspot. The eruption produced a full-halo CME, and the CME is coming our way. Last night, researchers said it might cause a G1-class geomagnetic storm upon reaching Earth’s vicinity. Since then, their prediction has been updated to G2. They are expecting the CME to arrive by April 14, 2022.

In the photo below, note the “S” shape of the filament as it erupts. Early X-ray solar telescopes, such as Yohkoh, were the first to see this S-shaped eruption on the sun clearly and report it widely, in the 1990s. Solar physicists call this S shape a sigmoid. We expect to see more of this sort of eruption as solar activity picks up. It is a signature of strongly built-up magnetic energy in the corona, usually in active regions, and consequently a sign of strong flaring potential and CME eruptions. A very useful signature for predicting strong eruptions!

Sun activity: Sun's red and roiling surface, with dark flare in S shape on brighter area.
S-shaped or “sigmoid” structure in the solar flare of April 11, 2022. Image via Helioviewer.org.
View of whole sun with bright S shape and inset of dark S shape.
Another good example of the S-shaped sigmoid structure like what we saw on the sun on April 11, 2022. However, this one is from February 12, 2007. Image via the JAXA/NASA Hinode XRT x-ray telescope.

Sun activity from April 11: Beautiful filament eruption

The sun’s activity picked up on April 11, 2022, with a beautiful filament eruption that simultaneously sent a CME heading our way. NOAA and NASA CME models are not out yet, but we expect the CME to reach Earth around April 13. We wait for updates throughout the day.

Filaments are long ropes of magnetism and solar material supported in the sun’s corona by magnetic fields tied to the sun. They’re the same thing as those great arcs, or prominences, we sometimes see extending from the limb, or edge, of the sun. They’re called filaments, instead of prominences, when seen centrally on the sun. Filaments may originate days to months before they become unstable and get launched into space. After their launch, they send a coronal mass ejection, or CME, hurtling outward.

The series of tweets below show the filament erupting in four different wavelengths of extreme ultraviolet light captured by the SDO spacecraft. First, we see a global view one wavelength after another; below, a closeup with all four wavelengths at the same time. Finally, using the SOHO/LASCO coronagraph, the CME shows up moving away from the sun towards Earth.

To our readers and community

We invite you all to send us your beautiful recent photos of sunspots and auroras! And we love receiving your photos! To those of you who’ve already posted a photo to our community, thank you.
Submit your image here
View community photos here

Recent sun activity and aurora photos from the EarthSky community

The sun, seen as a large monochromatic sphere with a mottled surface.
View at EarthSky Community Photos | Mario Rana in Hampton, Virginia, captured this filtered view of the sun (in hydrogen-alpha light) on April 17, 2022, and wrote: “Hydrogen-alpha image of today’s Sun with various active regions visible. AR2993 and AR2994 are rotating into view on the eastern limb.” Thank you, Mario!
April 16, 2022. Active sunspot group emerged on the north-east limb.
View at EarthSky Community Photos | Victor Rogus in Sedona, Arizona got this shot of the just emerging sunspot region on the north-east limb of the sun on April 16, 2022. He wrote: An active sunspot group is emerging over the sun’s northeastern limb. There are at least two dark cores larger than Earth, with a possibility of more spots trailing behind. This sunspot group has been very active, hurling CMEs and plumes of plasma over the edge of the sun. Future explosions may be Earth-directed. As seen to me this morning! Great capture Victor! Thank you!
The sun, seen as a large yellow sphere with a mottled surface.
View at EarthSky Community Photos | Mario Rana in Hampton, Virginia, captured this filtered close-up of the sun (at hydrogen-alpha wavelengths) on April 11, 2022. Thank you, Mario!
A pink and green aurora in Alberta, Canada.
View at EarthSky Community Photos. | Joel Weatherly in Edmonton, Alberta, Canada, captured this shot of the aurora borealis on April 10, 2022, during the G3 storm that happened on that night. He wrote: “Last night we were treated to a surprise G3-class geomagnetic storm. During the storm’s peak, auroras arced overhead and gained faint pinkish-red tinges. The bright star near the center is Vega, a brilliant sight in our springtime skies.” Beautiful photo, Joel! Thanks!

Bottom line: Sun activity for the week of April 11, 2022, is relatively low; however, there is some to look for. Sun observers expect the CME from an April 11 eruption on the sun to reach Earth April 14.

Click here for last week’s sun activity

Posted 
April 17, 2022
 in 
Sun

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Raúl Cortés

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