A Rare Type of Solar Storm Spotted by Satellite

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When a moderate-sized M-class flare erupted from the Sun on May 17, it sent out a barrage of high-energy solar particles that belied its initial intensity. These particles traveled at nearly the speed of light, crossing the 93 million miles between the Sun and Earth in a mere 20 minutes and impacting our atmosphere, causing cascades of neutrons to reach the ground — a rare event known as a ground level enhancement, or GLE.

The first such event since 2006, the GLE was recorded by a joint Russian/Italian spacecraft called PAMELA and is an indicator that the peak of solar maximum is on the way.

The PAMELA spacecraft — which stands for Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics — is designed to detect high-energy cosmic rays streaming in from intergalactic space. But on May 17, scientists from NASA’s Goddard Space Flight Center convinced the Russian team  in charge of PAMELA to grab data from the solar event occurring much closer to home.

This graph shows the neutrons detected by a neutron detector at the University of Oulu in Finland from May 16 through May 18, 2012. (University of Oulu/NASA's Integrated Space Weather Analysis System)

The result: the first observations from space of the solar particles that trigger the neutron storms that make up a GLE. Scientists hope to use the data to learn more about how GLEs are created, and why the May 17 “moderate” solar flare ended up making one.

“Usually we would expect this kind of ground level enhancement from a giant coronal mass ejection or a big X-class flare,” said Georgia de Nolfo, a space scientist at NASA’s Goddard Space Flight Center. “So not only are we really excited that we were able to observe these particularly high energy particles from space, but we also have a scientific puzzle to solve.”

Fewer than 100 GLEs have been recorded in the last 70 years, with the most powerful having occurred on February 23, 1956. Like most energetic solar outbursts, GLEs can have disruptive effects on sensitive electronics in orbit as well as on the ground, and based on recent studies may even have adverse effects on cellular systems and development.

The M-class flare from AR 1476 on May 17, 2012 (at right) Courtesy NASA/SDO and the AIA science team.

Read more on the NASA news release here.

How Big Was Monday’s CME?


April 16's M-class solar flare erupted with a CME that could dwarf the Earth, shown here to scale. (NASA/SDO/J. Major)

This big! The M1.7-class flare that erupted from active region 1461 on Monday, April 16 let loose an enormous coronal mass ejection many, many times the size of Earth, making this particular writer very happy that our planet was safely tucked out of aim at the time… and 93 million miles away.

The image above was obtained by NASA’s Solar Dynamics Observatory’s AIA 304 imaging instrument on Monday during the height of the event. I rotated the disk of the Sun 90 degrees to get a landscape look over the eastern limb, cropped it down and then added an Earth image to scale — just to show how fantastically huge our home star really is.

(Read “Watch it Rain on the Sun”)

Some minor editing was done to increase contrast and heighten detail in the eruption.

The CME was not directed our way, but it was aimed at NASA’s STEREO-B spacecraft, which will encounter the ejected material full-on.

Read more about this event in a previous Universe Today post here, and check out hi-def videos of the CME from SDO here.

Image credit: NASA/SDO and the AIA science team. Edited by Jason Major.

Giant Sunspot Seen Through Dusty Skies

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The enormous sunspot region responsible for all the recent fuss and flares was easily visible from Earth yesterday… easily visible, that is, with the help of a natural filter provided by a New Mexico dust storm!

Photographer David Tremblay captured this image on March 7 through the dust-laden sky of Alto, New Mexico. Active Region 1429 can be seen on the upper right side of the Sun’s disk. Many times the size of Earth, this sunspot region has already erupted with several X-class solar flares and sent numerous CMEs our way — with potential for more to come!

“Blowing dust from the Tularosa Basin is so very dense that observing the sun was possible with the naked eye this evening,” noted David on SpaceWeather.com, where you can see more of his solar photos taken about the same time.

The image above was captured at 560mm with a Canon MKlll ESO1D.

View more of David’s photography here.

Image © David Tremblay. All rights reserved. Used with permission.

Sun Releases a Powerful X5 Flare

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Active Region 1429 unleashed an X5.4-class solar flare early this morning at 00:28 UT, as seen in this image by NASA’s Solar Dynamics Observatory (AIA 304). The eruption belched out a large coronal mass ejection (CME) into space but it’s not yet known exactly how it will impact Earth — it may just be a glancing blow.

Solar flares are categorized by a scale according to their x-ray brightness. X is the strongest class, followed by M and then C-class. Within each class the numbers 1 through 9 subdivide the flares’ intensity.

A run-in with an X5-class flare is a major geomagnetic event that can cause radio blackouts on Earth and disrupt satellite operations, as well as intensify auroral activity.

The GOES satellite data for the March 7 flare is below:

The CME is expected to impact Earth sometime on the 8th or 9th. Check back here or at Spaceweather.com for updates on the storm (and any subsequent aurora photos!)

Also, check out the video below, assembled by the SDO team. Just after the X5.4-class flare another smaller X1-class flare occurred, sending a visible wave cross the Sun.


Image courtesy NASA, SDO and the AIA science team. And thanks to Camilla Corona SDO for all the updates!

Earth-Facing Sunspot Doubles in Size

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The latest sunspot region to traverse the face of the Sun has nearly doubled in size as it aims Earthward, as seen in the animation above from NASA’s Solar Dynamics Observatory. (Click image to play the animation.)

This is the second day in a row that the region has been seen expanding.

According to SpaceWeather.com, active region 1416 has the right sort of magnetic energy to potentially send M-class flares our way.

M-class flares are medium-sized solar flares. They can cause brief radio blackouts that affect Earth’s polar regions. Minor radiation storms sometimes follow an M-class flare event.

Sunspot region 1416 on Feb. 11, 2012. The large sunspot on the right is easily the size of Earth. (SDO/HMI Intensitygram)

If AR1416 produces a flare over the next 24 hours we would likely see increased auroral activity in upper latitudes early next week.

Stay tuned to Universe Today and SpaceWeather.com for any news on solar flares, and be sure to visit the SDO site for the latest images and videos of our home star.

Images courtesy NASA/SDO and the AIA and HMI science teams.

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Also, check out Alan Boyle’s article on MSNBC’s Cosmic Log about this and a recent heart-shaped coronal mass ejection that occurred on Friday, sending a cloud of charged particles on a Valentine’s Day date with our magnetosphere.  It should be a Sun-kissed night in northern parts of the world!

 

An Exoplanet’s Auroral Engine


Located 880 light-years away, a massive gas giant called CoRoT-2b orbits its star at a mere 2 million miles – less than a tenth the distance of Mercury’s orbit from the Sun. At this cozy proximity the star, CoRoT-2a, continually assaults the hot, gassy exoplanet with high-powered stellar winds and magnetic storms, stripping it of millions of kilograms of mass every day… and undoubtedly creating global auroras that rival even the most energetic seen on Earth.

But CoRoT-2b isn’t merely a tragic player in this stormy stellar performance; the planet itself may also be part of the cause.

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Almost 3 1/2 times the mass of Jupiter, CoRoT-2b (so named because it was discovered by the French Space Agency’s Convection, Rotation and planetary Transits space telescope, or CoRoT) orbits its star very rapidly, completing an orbit every 1.7 days. This in turn actually speeds up the rotation of the star itself thus generating even more magnetic activity, via a dynamo effect.

Caught up in this deadly dance, CoRoT-2b is losing mass at an estimated rate of 150 million billion kilograms of material every year! The planet would likely have a long comet-like tail of this stripped material trailing behind it.

Although this sounds like a lot, CoRoT-2b has enough mass to keep “spinning up” its star for thousands of billions of years.

Read more about CoRoT-2a and b here.

Video: [email protected]

Tiny Stars with a Big Flares

This is an artist's concept of a red dwarf star undergoing a powerful eruption, called a stellar flare. A hypothetical planet is in the foreground. Credit: NASA/ESA/G. Bacon (STScI)

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For a long time, astronomers have known that stars often have troubled childhoods. They suffer from frequent and violent flares. But eventually, as they settle onto the main sequence, stars grow out of their destructive ways, which is thankful for us since large flares could do some serious damage to our biosphere. A new study confirms expectations that some stars never outgrow their roguish ways and that the smallest stars can be prone to the most frequent flares.

The study uses data from the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) survey conducted by the Hubble Space Telescope. This survey was conducted over a seven day period in 2006 and originally designed to search for transiting planets by repeatedly imaging over 200,000 stars for sings of transits. However, since the exploration contained so many red dwarf stars, the smallest and most common stars in the universe, a team led by Rachel Osten of the Space Telescope Science Institute was able to use it to constrain the rate of flares on these diminutive stars.

The team eventually discovered 100 stellar flares, some of which increased the overall brightness of their parent star by as much as 10%. In general, most flares were short, lasting on average a mere 15 minutes. Some stars flared multiple times. These flares weren’t limited to simply young stars, but also, highly evolved stars, including several variable stars which appeared to flare more often.

“We discovered that variable stars are about a thousand times more likely to flare than non-variable stars,” Adam Kowalski, another team member, says. “The variable stars are rotating fast, which may mean they are in rapidly orbiting binary systems. If the stars possess large star spots, dark regions on a star’s surface, that will cause the star’s light to vary when the spots rotate in and out of view. Star spots are produced when magnetic field lines poke through the surface. So, if there are big spots, there is a large area covered by strong magnetic fields, and we found that those stars had more flares.”

Part of the reason that dwarf stars are though to flare more comes from the fact that they have deep convection zones (shown by their lack of lithium in the photosphere which is destroyed by convection which drags it to depths hot enough to destroy it). This bulk movement of ionized particles creates a dynamo and strong magnetic fields on the star. When these fields become especially tangled, they can snap and spontaneously reform in a lower energy state. The energy lost is dumped into the stars outer layers, heating them with tremendous amounts of energy and releasing large amounts of ultraviolet, X-ray, and even gamma radiation as well as charged particles. In more extreme circumstances, the fields don’t immediately reform but swing outwards as they unwind themselves, dragging large amounts of the star with it, and flinging it outwards in a coronal mass ejection (CME).

One of the results of the enhanced magnetic activity is a larger number and size of sunspots. According to Osten, “Sunspots cover less than 1 percent of the Sun’s surface, while red dwarfs can have star spots that cover half of their surfaces.”

Solar Explosions Spark Controversy

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Nowhere in the Solar System are conditions more extreme than the Sun. Every second it converts millions of tons of matter into energy to create the intense levels of heat and light we expect of our local star. Study the Sun in different wavelengths and its violent nature can really become apparent. The STEREO satellite has been studying the Sun at a wavelength of 304Å and the results support a controversial solar theory.

Coronal Mass Ejections (or CMEs) are common on the Sun and they have a very real impact to us here on Earth. The solar explosions expel trillions of trillions of tons of super hot hydrogen gas into space, sometimes in the direction of the Earth. Traveling at speeds up to 2,000 kilometers per second it takes just a day for the magnetized gas to reach us and on arrival it can induce strong electric currents in the Earth’s atmosphere leading not only to the beautiful auroral displays but also to telecommunication outages, GPS system failures and even disturbances to power grids.

Solar flares, to use their other name, were first observed back in 1859 and since then, scientists have been studying them to try to understand the mechanism that causes the eruption. It has been known for some time that the magnetically charged gas or plasma is interacting with the magnetic field of the Sun but the detail has been at best, elusive.

In 2006, the international satellite STEREO was launched with the objective of continuously monitoring and studying the CMEs as they head toward the Earth and its data has helped scientists at the Naval Research Laboratory (NRL) in Washington, D.C., start to understand the phenomenon.

Using this new data, scientists at the NRL compared the observed activity with a controversial theory that was first proposed by Dr James Chen (also from the NRL) in 1989. His theory suggested that the erupting clouds of plasma are giant ‘magnetic flux ropes’, effectively a twisted up magnetic field line shaped like a donut. The Sun being a vast sphere of gas suffers from differential rotation where the polar regions of the Sun and the equatorial regions all rotate at different speeds. As a direct result of this, the plasma ‘drags’ the magnetic field lines around and the Sun and it gets more and more twisted up . Eventually, it bursts through the surface, taking some plasma with it giving us one of the most dramatic yet potentially destructive events in the Universe.

Dr Chen and a Valbona Kunkel, a doctorate student at George Mason University, applied Dr. Chen’s model to the new data from STEREO and found that the theory agrees with the measured trajectories of the ejected material. It therefore looks like his theory, whilst controversial may have been right all along.

Its strange to think that our nearest star, the Sun, still has secrets. Yet thanks to the work of Dr. Chen and his team, this one seems to have been unraveled and understanding the strange solar explosions will perhaps help us to minimise impact to Earth based technologies in years to come.

Mark Thompson is a writer and the astronomy presenter on the BBC One Show. See his website, The People’s Astronomer, and you can follow him on Twitter, @PeoplesAstro

Hinode Discovers the Sun’s Hidden Sparkle

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Blinking spots of intense light are being observed all over the lower atmosphere of the Sun. Not just in the active regions, but in polar regions, quiet regions, sunspots, coronal holes and loops. These small explosions fire elegant jets of hot solar matter into space, generating X-rays as they go. Although X-ray jets are known to have existed for many years, the Japanese Hinode observatory is seeing these small flares with unprecedented clarity, showing us that X-ray jets may yet hold the answers to some of the most puzzling questions about the Sun and its hot corona.

Although a comparatively small mission (weighing 875 kg and operating just three instruments), Hinode is showing the world some stunning high resolution pictures of our nearest star. In Earth orbit and kitted out with an optical telescope (the Solar Optical Telescope, SOT), Extreme ultraviolet Imaging Spectrometer (EIS) and an X-Ray Telescope (XRT), the light emitted from the Sun can be split into its component optical, ultraviolet and X-ray wavelengths. This in itself is not new, but never before has mankind been able to view the Sun in such detail.

It is widely believed that the violent, churning solar surface may be the root cause of accelerating the solar wind (blasting hot solar particles into space at a mind-blowing 1.6 million kilometers per hour) and heating the million plus degree solar atmosphere. But the small-scale processes close to the Sun driving the whole system are only just beginning to come into focus.

Up until now, small-scale turbulent processes have been impossible to observe. Generally, any feature below 1000 km in size has remained undetected. Much like trying to follow a golf ball in flight from 200 meters away, it is very difficult (try it!). Compare this with Hinode, the same golf ball can be resolved by the SOT instrument from nearly 2000 km away. That’s one powerful telescope!

The limit of observable solar features has now been lifted. The SOT can resolve the fine structure of the solar surface to 180 km, this is an obvious improvement. Also, the EIS and XRT can capture images very quickly, one per second. The SOT can produce hi-res pictures every 5 minutes. Therefore, fast, explosive events such as flares can be tracked easier.

Putting this new technology to the test, a team led by Jonathan Cirtain, a solar physicist at NASA’s Marshall Space Flight Center, Huntsville, Alabama, has unveiled new results from research with the XRT instrument. X-ray jets in the highly dynamic chromosphere and lower corona appear to occur with greater regularity than previously thought.

X-ray jets are very important to solar physicists. As magnetic field lines are forced together, snap, and form new configurations, vast quantities of heat and light are generated in the form of a “microflare”. Although these are small events on a solar scale, they still generate huge amounts of energy, heating solar plasma to over 2 million Kelvin, create spurts of X-ray emitting plasma jets and generate waves. This is all very interesting, but why are jets so important?

The solar atmosphere (or corona) is hot. In fact, very hot. Actually, it is too hot. What I’m trying to say is that measurements of coronal particles tell us the atmosphere of the Sun is actually hotter than the Suns surface. Traditional thinking would suggest that this is wrong; all sorts of physical laws would be violated. The air around a light bulb isn’t hotter than the bulb itself, the heat from an object will decrease the further away you measure the temperature (obvious really). If you’re cold, you don’t move away from the fire, you get closer to it!

The Sun is different. Through interactions near the surface of the Sun between plasma and magnetic flux (a field known as “magnetohydrodynamics” – magneto = magnetic, hydro = fluid, dynamics = motion: “magnetic-fluid-motion” in plain English, or “MHD” for short), MHD waves are able to propagate and heat up the plasma. The MHD waves under scrutiny are known as “Alfvén wavesâ€? (named after Hannes Alfvén, 1908-1995, the plasma physics supremo) which, theoretically, carry enough energy from the Sun to heat the solar corona hotter than the solar surface. The one thing that has dogged the solar community for the last half a century is: how are Alfvén waves produced? Solar flares have always been a candidate as a source, but observation suggested that there wasn’t enough flares to generate enough waves. But now, with advanced optics used by Hinode, many small-scale events appear to be common… bringing us back to our X-ray jets…

Previously, only the largest X-ray jets have been observed, putting this phenomenon at the bottom of the priority list. NASA’s Marshall Space Flight Center group has now turned this idea on its head by observing hundreds of jet events each and every day:

“We now see that jets happen all the time, as often as 240 times a day. They appear at all latitudes, within coronal holes, inside sunspot groups, out in the middle of nowhere–in short, wherever we look on the sun we find these jets. They are a major form of solar activity” – Jonathan Cirtain, Marshall Space Flight Center.

So, this little solar probe has very quickly changed our views on solar physics. Launched on September 23, 2006, by a consortium of countries including Japan, USA and Europe, Hinode has already revolutionized our thinking about how the Sun works. Not only looking deep into the chaotic processes in the solar chromosphere, it is also finding new sources where Alfvén waves may be generated. Jets are now confirmed as common events that occur all over the Sun. Could they provide the corona with enough Alfvén waves to heat the Sun’s corona more than the Sun itself? I don’t know. But what I do know is, the sight of solar jets flashing to life in these movies is awesome, especially as you see the jet launch into space from the original flash. This is also a very good time to be seeing this amazing phenomenon, as Jonathan Cirtain points out the site of solar jets reminds him of “the twinkle of Christmas lights, randomly oriented. It’s very pretty”. Even the Sun is getting festive.