Something New On the Sun: SDO Spots a Late Phase in Solar Flares

From a NASA press release:

The Sun’s surface dances. Giant loops of magnetized solar material burst up, twist, and fall back down. Some erupt, shooting radiation flares and particles out into space. Forced to observe this dance from afar, scientists use all the tools at their disposal to look for patterns and connections to discover what causes these great explosions. Mapping these patterns could help scientists predict the onset of space weather that bursts toward Earth from the Sun, interfering with communications and Global Positioning System (GPS) signals.

Analysis of 191 solar flares since May 2010 by NASA’s Solar Dynamics Observatory (SDO) has recently shown a new piece in the pattern: some 15 percent of the flares have a distinct “late phase flare” some minutes to hours later that has never before been fully observed. This late phase of the flare pumps much more energy out into space than previously realized.

“We’re starting to see all sorts of new things,” says Phil Chamberlin, deputy project scientist for SDO at NASA’s Goddard Space Flight Center in Greenbelt, Md. “We see a large increase in emissions a half-hour to several hours later, that is sometimes even larger than the original, traditional phases of the flare. In one case on November 3, 2010, measuring only the effects of the main flare would mean underestimating the amount of energy shooting into Earth’s atmosphere by 70 percent.”

The entire space weather system, from the Sun’s surface to the outer edges of the solar system, is dependent on how energy transfers from one event to another – magnetic reconnection near the Sun transferred to movement energy barreling across space to energy deposited into Earth’s atmosphere, for example. Better understanding of this late phase flare will help scientists quantify just how much energy is produced when the sun erupts.

The team found evidence for these late phases when SDO first began collecting data in May of 2010 and the Sun decided to put on a show. In that very first week, in the midst of an otherwise fairly quiet time for the sun, there sprouted some nine flares of varying sizes. Flare sizes are divided into categories, named A, B, C, M and X, that have long been defined by the intensity of the X-rays emitted at the flare’s peak as measured by the GOES (Geostationary Operational Environmental Satellite) satellite system. GOES is a NOAA-operated network of satellites that has been in geosynchronous orbit near Earth since 1976. One of the GOES satellites measures only X-ray emissions and is a crucial source of information on space weather that the sun sends our way.

That May 2010, however, SDO observed those flares with its multi-wavelength vision. It recorded data indicating that some other wavelengths of light weren’t behaving in sync with the X-rays, but peaked at other times.

“For decades, our standard for flares has been to watch the x-rays and see when they peak,” says Tom Woods, a space scientist at the University of Colorado, Boulder, Colo. who is first author on a paper on this subject that goes online September 7 in the Astrophysical Journal. “That’s our definition for when a flare goes off. But we were seeing peaks that didn’t correspond to the X-rays.” Woods says that at first they were worried the data were an anomaly or a glitch in the instruments. But as they confirmed the data with other instruments and watched the patterns repeat over many months, they began to trust what they were seeing. “And then we got excited,” he says.

Over the course of a year, the team used the EVE (for Extreme ultraviolet Variability Experiment) instrument on SDO to record data from many more flares. EVE doesn’t snap conventional images. Woods is the principal investigator for the EVE instrument and he explains that it collects all the light from the sun at once and then precisely separates each wavelength of light and measures its intensity. This doesn’t produce pretty pictures the way other instruments on SDO do, but it provides graphs that map out how each wavelength of light gets stronger, peaks, and diminishes over time. EVE collects this data every 10 seconds, a rate guaranteed to provide brand new information about how the sun changes, given that previous instruments only measured such information every hour and a half or didn’t look at all the wavelengths simultaneously – not nearly enough information to get a complete picture of the heating and cooling of the flare.


Recording extreme ultraviolet light, the EVE spectra showed four phases in an average flare’s lifetime. The first three have been observed and are well established. (Though EVE was able to measure and quantify them over a wide range of light wavelengths better than has ever been done.) The first phase is the hard X-ray impulsive phase, in which highly energetic particles in the sun’s atmosphere rain down toward the sun’s surface after an explosive event in the atmosphere known as magnetic reconnection. They fall freely for some seconds to minutes until they hit the denser lower atmosphere, and then the second phase, the gradual phase, begins. Over the course of minutes to hours, the solar material, called plasma, is heated and explodes back up, tracing its way along giant magnetic loops, filling the loops with plasma. This process sends off so much light and radiation that it can be compared to millions of hydrogen bombs.

The third phase is characterized by the Sun’s atmosphere — the corona –losing brightness, and so is known as the coronal dimming phase. This is often associated with what’s known as a coronal mass ejection, in which a great cloud of plasma erupts off the surface of the Sun.

But the fourth phase, the late phase flare, spotted by EVE was new. Anywhere from one to five hours later for several of the flares, they saw a second peak of warm coronal material that didn’t correspond to another X-ray burst.

“Many observations have spotted an increased extreme ultraviolet peak just seconds to minutes after the main phase of the flare, and this behavior is considered a normal part of the flare process. But this late phase is different,” says Goddard’s Chamberlin, who is also a co-author on the paper. “These emissions happen substantially later. And it happens after the main flare exhibits that initial peak.”

To try to understand what was happening, the team looked at the images collected from SDO’s Advanced Imaging Assembly (AIA) as well. They could see the main phase flare eruption in the images and also noticed a second set of coronal loops far above the original flare site. These extra loops were longer and become brighter later than the original set (or the post-flare loops that appeared just minutes after that). These loops were also physically set apart from those earlier ones.

“The intensity we’re recording in those late phase flares is usually dimmer than the X-ray intensity,” says Woods. “But the late phase goes on much longer, sometimes for multiple hours, so it’s putting out just as much total energy as the main flare that typically only lasts for a few minutes.” Because this previously unrealized extra source of energy from the flare is equally important to impacting Earth’s atmosphere, Woods and his colleagues are now studying how the late phase flares can influence space weather.

The late phase flare is, of course, just one piece of the puzzle as we try to understand the star with which we live. But keeping track of the energy, measuring all the different wavelengths of light, using all the instruments NASA has at its disposal, such information helps us map out all the steps of the Sun’s great dance.

Sun Erupts with Spectacular Flares

The Sun sent two flares yesterday from active region 1283. This video shows the second flare, at 6:12 p.m. EDT (2212 GMT) on Tuesday an even bigger flare than the M-class flare from early on Sept. 6, at about 0150 GMT. This was an X-class flare, major events that can trigger planet-wide radio blackouts and long-lasting radiation storms. The latest update says the CMEs could sail north of Earth, delivering a glancing blow to Earth’s magnetic field, and could arrive between September 8 -10. says high-latitude sky watchers should be alert for auroras in the nights ahead.

The image below was sent in to Universe Today by Monty Leventhal showing the type 4B Flare with an X-ray class of X-2 in active region 1283.


Here are the details and equipment Monty used:

Date:- 6-9-11
Time:- 22.05 U.T.
Conditions:- Poor
Camera:- Canon 300D
Filter:- H-alpha. 6Å.
Telescope:- Meade S.C. 10 inch

SDO’s Guide to Solar Flares

X-Class, M-Class, C-Class… What does it all that mean, and just what is a solar flare? This video from the Solar Dynamics Observatory tells all about solar flares and how they might affect us here on Earth. Find out why NASA and NOAA are constantly monitoring the Sun for activity that could create long lasting radiation storms which can harm satellites, communications systems, and even ground-based technologies and power grids.

Sun Erupts with Largest Solar Flare of the Cycle

Early Tuesday morning (August 9, 2011,) the Sun erupted with the largest solar flare of Cycle 24, registering as an X7-class flare. This flare had an X-ray magnitude of X6.9, meaning it was more than 3 times larger than the previous largest flare of this solar cycle – the X2.2 that occurred on Feb 15, 2011, NASA said. The source was Sunspot 1263 which is nearing the western limb of the Sun, and because of its location, scientists do not anticipate that this explosion will hit Earth directly. Therefore, the impact on communications and electric grids will likely (and luckily) be minimal.
Continue reading “Sun Erupts with Largest Solar Flare of the Cycle”

How Big Are Solar Flares?

With the recent activity on the Sun, we’ve used the words “massive” or “huge” to describe solar flares. But just how big are they, really? This great video explains and illustrates the actual size of solar flares.

Thanks to Scott Stevenson for creating and sending us the video. Scott notes that text subtitles are available if you click on the “CC” button on the bottom of the video screen, making this informative video accessible to a wider audience.

Solar Storm Heading Our Way

Early today, (Aug 3, 2011) two active regions on the Sun, sunspot 1261 and 1263 unleashed solar flares, which was captured by NASA’s Solar Dynamics Observatory. The above video shows an M6 class flare from 1261 in a couple of different wavelengths. SolarstormWatch, a citizen science project through the Royal Observatory in Greenwich, England predicts the solar storm from the larger flare to reach Earth at 15:00 UTC on August 5, 2011, and also predict direct hit on Earth.

See below for a graph of the activity:


Solar storms are a concern if they hit Earth directly since under the right conditions, they can create extra electrical currents in Earth’s magnetosphere. The electrical power grid is vulnerable to any extra currents, which can infiltrate high-voltage transmission lines, causing transformers to overheat and possibly burn out.

Check and the National Weather Service’s Space Weather Prediction Center for more information.

Interacting Sunspots Spawn Gigantic Solar Flare

From a RAS press release:

The largest solar flare recorded in nearly five years was triggered by interactions between five rotating sunspots, say researchers who studied observations of the flaring region of the Sun taken by the Solar Dynamics Observatory over a period of five days. The flare occurred at 1.44am on February 15,2011, when the Sun released the largest recorded solar flare since December 2006 and the first flare of the current solar cycle to be classified as the most powerful “X-class”.
Continue reading “Interacting Sunspots Spawn Gigantic Solar Flare”

Sun Erupts with Enormous X2 Solar Flare

Just in time for Valentine’s Day, [and the Stardust flyby of Comet Tempel 1] the Sun erupted with a massive X-Class flare, the most powerful of all solar events on February 14 at 8:56 p.m. EST . This was the first X-Class flare in Solar Cycle 24 and the most powerful X-ray flare in more than four years.

The video above shows the flare as imaged by the AIA instrument at 304 Angstroms on NASA’s Solar Dynamics Observatory. More graphic videos below show the flare in the extreme ultraviolet wavelength of 193 Angstroms and as a composite with SOHO’s coronagraph.

Spaceweather Update: A CME hit Earth’s magnetic field at approximately 0100 UT on Feb. 18th (8:00 pm EST on Feb. 17th). Send me or comment your aurora photos

The eruption registered X2 on the Richter scale of solar flares and originated from Active Region 1138 in the sun’s southern hemisphere. The flare directly follows several M-class and C-class flares over the past few days which were less powerful. The explosion also let loose a coronal mass ejection (CME) headed for Earth’s orbit. It was speeding at about 900 Km/second.
CME’s can disrupt communications systems and the electrical power grid and cause long lasting radiation storms.

According to a new SDO update, the particle cloud from this solar storm is weaker than first expected and may produce some beautiful aurora in the high northern and southern latitudes on Feb. 17 (tonight).

According to, skywatchers in the high latitudes should be alert for auroras after nightfall Feb. 17 from this moderately strong geomagnetic storm.

Send me your aurora reports and photos to post here

Sources: SDO website,

NASA SDO – Big, Bright Flare February 15, 2011

Video Caption: Active region 1158 let loose with an X2.2 flare at 0153 UT or 8:50 pm ET on February 15, 2011, the largest flare since Dec. 2006 and the biggest flare so far in Solar Cycle 24. Active Region 1158 is in the southern hemisphere, which has been lagging the north in activity but now leads in big flares! The movie shows a close-up of the flaring region taken by the Solar Dynamics Observatory in the extreme ultraviolet wavelength of 193 Angstroms. Much of the vertical line in the image and the staggered lines making an “X” are caused by the bright flash overwhelming our imager. A coronal mass ejection was also associated with the flare. The movie shows activity over about two days (Feb. 13-15, 2011). Since the active region was facing Earth, there is a good chance that Earth will receive some effects from these events, with some possibility of mid-latitude aurora Feb. 16 – 18. Credit: NASA SDO

X2 flare Video combo from SDO and SOHO

Video caption: The X2 flare of Feb. 15, 2011 seen by SDO (in extreme ultraviolet light) enlarged and superimposed on SOHO’s coronagraph that shows the faint edge of a “halo” coronal mass ejection as it races away from the Sun. The video covers about 11 hours


This image taken by SDO's AIA instrument at 171 Angstrom shows the current conditions of the quiet corona and upper transition region of the Sun. Credit: NASA/SDO/AIA

Solar Flares Can Now Be Predicted More Accurately

We all like to know in advance what the weather is going to be like, and space weather is no different. However, predicting solar storms from the sun — which can disrupt satellites and even ground-based technologies — has been difficult. But now scientists say magnetic loops breaking inside the sun provide two to three-day warnings of solar flares. “For the first time, we can tell two to three days in advance when and where a solar flare will occur and how large it will be,” said Alysha Reinard, from the NOAA Space Weather Prediction Center.

Reinard and her team found that sound waves recorded from more than 1,000 sunspot regions reveal disruptions in the sun’s interior magnetic loops that predict a solar flare. They found the same pattern in region after region: magnetic twisting that tightened to the breaking point, burst into a large flare, and vanished. They established that the pattern could be used as a reliable tool for predicting a solar flare.

“These recurring motions of the magnetic field, playing out unseen beneath the solar surface, are the clue we’ve needed to know that a large flare is coming—and when,” said Reinard.

Twisting magnetic fields beneath the surface of the sun erupt into a large solar flare, as shown above. Credit: NOAA

The new technique is already twice as accurate as current methods, according to the authors, and that number is expected to improve as they refine their work over the next few years. With this technique, reliable watches and warnings should be possible before the next solar sunspot maximum, predicted to occur in 2013.
“Two or three days lead time can make the difference between safeguarding the advanced technologies we depend on every day for our livelihood and security, and the catastrophic loss of these capabilities and trillions of dollars in disrupted commerce,” said Thomas Bogdan, director of NOAA’s Space Weather Prediction Center.

The team’s paper has been accepted for publication by the Astrophysical Journal Letters.

Source: NOAA

Eclipse Sunspots Signal Increased Activity


Astrophotographers capturing the recent annular solar eclipse on January 15, 2010 got an added bonus: upon closer inspection, they found sunspot 1040 also showed up on their images, too. “We didn’t mean to catch sunspots in our Jaffna Eclipse expedition, nor did we plan to,” said Prasanna Deshapriya, one of the members of the Eclipse Hunt 2010 crew, featured in our eclipse photo and video collection. “But surprisingly this is what really happened.”

SOHO image of sunspot 1040 on January 15, 2010. credit: SOHO/MDI

The rather big sunspot 1040, which was also captured by the SOHO spacecraft on Jan. 15 has just disappeared over the sun’s western limb, currently leaving the visible disk of the sun blank once again in this uncharacteristically long solar minimum. But our old friend, sunspot 1039 should be showing up soon, as the sun rotates around. We know it is still there, because the STEREO spacecraft can show us what is going on the sun’s far side. Sunspot 1039 should emerge for direct viewing from Earth within the next 48 hours. encourages those amateur astronomers with solar telescopes to monitor the Sun’s east limb for developments.

STEREO B captures the largest solar flare in two years. Click for larger movie.

Additionally on Jan. 19th at 1340 UT, STEREO-B recorded the strongest solar flare in almost two years. Click the image to see the action on an ultraviolet movie of the blast. The M2-class eruption came from sunspot 1039, so that sunspot is likely still very active. said that considering the sunspot was not even visible from Earth at the time of the eruption, the flare was probably much stronger than its M2 classification would suggest. This active region has produced at least three significant eruptions since Jan. 17th and it shows no signs of cooling off.

Sources: Eclipse 2010 blog, from 01/19/2010 ,