Archive for category User Highlights
and the second one shows the same feature further onto disk:
These movies show motions in a solar prominence. Prominences are clouds of relatively cool plasma magnetically suspended in the hotter surrounding solar atmosphere. By studying the motions and oscillations in a prominence, we can gain insight into their dynamic structure. A longer term research goal is to understand what makes some prominences unstable and erupt into space, while others don’t.
This image in the AIA 304 channel shows the same prominence:
You can see from this picture that the prominence extends for a considerable distance, and appears to bend.
Thanks for sharing these movies, CuriousTess!
Yesterday the Sun showed off a series of spectacular prominence eruptions that were recorded by many users.
Prominences are relatively cool, dense clouds of plasma that lie suspended in Sun’s magnetic field, sometimes for weeks. Occasionally, they become unstable and they erupt.
YouTube user 38starman posted these full disk movies of the Sun. The first is in AIA 304: this waveband sees plasma at around 50,000 K
and this is taken in PROBA2 173
It is possible that one event may have triggered another. Understanding the connection between separate events is a big part of Solar Dynamics Observatory science.
YouTube user коля павл posted a close-up of the prominence towards the south, this time in AIA 131
AIA 131 picks up temperatures at around 400,000 K, 10,000,000 K and 16,000,000 K. By looking at the AIA 304 images, it seems more likely that the prominence has plasma at around 50,000 and 400,000 K. The hotter temperatures that AIA 131 can see occur in flares, which are much more dynamic events than prominences. This is a good example demonstrating that the images we see can contain features at different temperatures.
Multiple wavebands really help us understand the true temperature of features on the Sun.
As the movie progresses, you see a small eruption take place. As the eruption starts, you can clearly see the southern base of the loop displace. The loop appears to be released in some way, which shakes the whole loop along its entire length. This event is a great example of a transverse coronal loop oscillation. These were first observed by the Transition Region and Coronal Explorer (TRACE) in 1998. Since these initial observations, many more examples have been observed, by both TRACE and AIA. The mechanism of the excitation of these waves remains hidden, but it can be connected with a blast wave generated in a flare epicentre. For scale, the Earth is roughly the same size as the Helioviewer logo in the bottom right hand corner of the movie.
although it is much more difficult to see in the AIA 193 Angstrom channel compared to the AIA 171 Angstrom channedl(the dark wavy material you see are motions in a prominence, not the same as the coronal loop oscillation).
Observations of coronal loop oscillations, coupled with a theoretical understanding of how these oscillations behave in the coronal plasma has lead to a new field of study called coronal seismology. Coronal seismology is analogous to seismology on Earth. Seismology is the study of earthquakes and the propagation of waves arising from earthquakes, and can be used to infer properties of the structure of the Earth. Similarly, coronal seismology is used to measure properties of the Sun’s coronal plasma. Using coronal seismology, we can derive the density and magnetic field of the coronal plasma, measurements that are difficult make in other ways.
YouTube and Helioviewer.org user otraLoly shared this short video of the return of Comet 96P/Machholz to the LASCO-C3 field of view. Thanks for sharing your video! More images of the comet will be available soon on Helioviewer.org.
Comet 96P/Machholz has an orbital period of about 5.2 years, which means it has been seen before in LASCO observations. Here is an example image from 2007
and five years before that in 2002,
The dates for the entry of Comet 96P/Machholz were obtained from the transit page of the LASCO instrument. It is projected to be visible in the LASCO C3 field of view from July 12 – 17, and it may also be visible in the images from the STEREO A/B coronagraphs.
Here are some of the many excellent videos made by Helioviewer.org users of the Transit of Venus seen by AIA…
What happened? Well, there was an eruption on the back side of the Sun, that caused a propagating disturbance in the solar atmosphere. that appears to have triggered a prominence lift-off on the front-side of the Sun. This is a great example of how the high cadence, continuous observations from Solar Dynamics Observatory give us a much better view of how distant parts of the Sun can physically influence each other. We liked this event so much we made and uploaded some movies of our own. The lower cadence of these movies allows you to see the swaying of coronal material in response to the disturbance from the initial eruption.
A colleague who works with LASCO data yesterday found this lovely spiralling eruption close to the south pole.
It’s a great example of how the magnetic field can influence the dynamics of erupting plasma. The eruption starts around 00:13 in the above video.
YouTube and Helioviewer.org user sedge2002 found another coronal cavity. This one was on the Sun late 2011 to early 2012. It appears towards the end of this movie, at around 30-45 degrees clockwise from the north pole of Sun, above the limb:
Thanks to sedge2002 for making this movie and sharing it with other users of Helioviewer.org. As the movie demonstrates, coronal cavities do occur, and so the one you may have earlier in the week, whilst a great example of a coronal cavity, is definitely not unique. What is a coronal cavity? Let Dr. Alex Young of the The Sun Today tell you:
The material travels in to the field of view from its launch location, which can be seen in STEREO-B EUVI images. If you go to STEREO latest image selector and select ‘Behind EUVI 195’, pick a resolution of 512 x 512, type in a start and end date of 20120202, and select ‘Slideshow’, you get an animation of the event as seen from STEREO-B. There is a filament eruption on the upper left of the disk (it is hard to spot) which is the same material seen in the AIA 304 movie above:
Thanks to goggog67 for spotting this event and sharing it with us!
The coronal mass ejection associated with the flare event of 23 January 2012 has just been spotted by the Advanced Composition Explorer (ACE) spacecraft. ACE orbits the L1 libration point which is a point of Earth-Sun gravitational equilibrium about 1.5 million km from Earth and 148.5 million km from the Sun. From its location at L1 ACE has a prime view of the solar wind, interplanetary magnetic field and higher energy particles accelerated by the Sun, as well as particles accelerated in the heliosphere and the galactic regions beyond.
You can check here for recent observations of the distribution of the aurora borealis from space, courtesy of the NOAA Polar Operational Environmental Satellite. NOAA also have a test data product and webpage that shows the output of a model that predicts the probability of seeing the aurora. You can keep informed on the latest space weather activity at NOAA Space Weather Prediction Center and the Integrated Space Weather Laboratory.
Here are some more movies of the original event shared by our users – thanks to everyone!
YouTube and Helioviewer.org user losyziemi shared this video of the eruption and the consequent view in LASCO C2 and C3. Those streaks and dots are due to particles accelerated by the event impacting the detectors of LASCO C2 and C3
YouTube and Helioviewer.org user otraLoly shared this video of the eruption, concentrating on AIA 171 and LASCO C2.
As you will already know since you are reading this, Helioviewer Project services have now returned to nominal operations earlier than anticipated. Thanks to all those concerned for their work and for keeping the downtime to a minimum!
Just before our scheduled outage, many of our users caught sight of a flaring active region (videos below). Well, since then the Solar Weather Prediction Center
“has issued a Geomagnetic Storm Watch with G2 level storming likely and G3 level storming possible, with the storm continuing into Wednesday, Jan 25. All of this activity is related to a moderate (R2) Radio Blackout x-ray flare that erupted Sunday night (11pm EST).”
which the self-same flaring event spotted by our users. This is a developing story – please consult the Solar Weather Prediction Center for more updates on the progress of the storm. There is great animation of the predicted progress of the coronal mass ejection through interplanetary space as it comes towards Earth here. Geomagnetic storms are temporary disturbances in the Earth’s magnetic field; this one is predicted to be moderate, possibly strong. On average, there are a few of these every year; the good news is that if you haven’t noticed one before, you’re probably not going to notice this one.
I’ve included some videos of the flaring event below, made by Helioviewer users and shared with Helioviewer and YouTube users – thanks everyone!
YouTube user Idontwannastopat6
Nice close-up of the flare in SDO/AIA 304 ansgtrom from YouTube user 666redwater.
YouTube user 666redwater also made a zoomed-out video of this event using the SDO/AIA 131 filter. In this filter you see very different structures compared to SDO/AIA 304 and 171. There are a total of 10 filters of AIA, each of them telling us something different about the structure of the sun’s atmosphere.
YouTube and users losyziemi, MeireRuiz7 and goggog67 have created a wonderful series of movies that show a flaring system of loops coming from a source active region just coming round the limb of the Sun. Thanks for sharing these great movies!
Solar flares are caused by the interaction of particles accelerated by magnetic reconnection with the surrounding plasma. In the movies below, you can see bright loop-top sources filling in their supporting loops. This caused by the flare-accelerated particles striking the surrounding plasma, and heating it up; as that plasma cools down, it appears in the AIA wavebands. This event should be visible in all the other AIA wavebands (which correspond approximately to different temperatures in the solar plasma).
Comet Lovejoy will be passing close to the Sun in the next couple of days. SDO will be taking special observations of the comet beginning 22:59 UT on 2011/12/15 (5.59pm 2011/12/15, Eastern Time), and lasting for a couple of hours. The comet will pass behind the solar limb at around 00:07 UT 2011/12/16 (7:07pm 2011/12/15, Eastern Time). There is a chance the comet will survive its encounter with the Sun.
SDO/AIA will take special observations to view the comet; AIA will change its pointing and point slightly away from the center of the Sun in order to try to get more observations of the comet as it gets close to the disk of the Sun.
Why are these observations being taken? Well, we are looking for something like we saw on 2011/07/05 this year. On that day a comet fell in to the Sun. These kinds of comets have been seen before in LASCO-C3 and LASCO-C2 images. What was new about this observation was that for the first time the comet was seen against the disk of the Sun. The video below gives a description of what was seen.
SDO/AIA detects different wavelengths of light. So in order for us to see it, the comet must have been emitting at those different wavelengths, and the comet must have disintegrated in to a big enough cloud of ionized gas for us to see it. So the big scientific question about seeing this comet against the disk of the Sun is explaining both how it came to be emitting at wavelengths that SDO/AIA could see, and figuring out how it could have disintegrated. This is an active area of research, with presentations on this subject given last week at the American Geophysical Union‘s Fall Meeting, and a paper set to appear in Science.
We hope you enjoy tracking Comet Lovejoy as it gets closer to the Sun. Please let us know if you have any further questions about the Helioviewer Project and Comet Lovejoy.
The filament(1) is the narrow dark moving thread in the middle of the field of view. As the movie progresses the filament evolves and eventually erupts out in to space, causing a coronal mass ejection. The material underneath the filament darkens, indicating an evacuation of plasma, that is, the plasma is draining away from that part of the solar atmosphere. These kinds of events happen a lot, and will happen more as solar activity ramps up. Thank you, muriealdurian, for uploading a good example of a filament eruption.
(1) Prominences are filaments seen over the limb of the Sun – prominences and filaments are the same thing, but have different names for historical reasons. Prominences and filaments were first observed in different wavelengths, and so acquired different names. Later, we realized that they were the same thing, but the two names have stuck around in the literature.
Helioviewer user otraLoly was first to share this rather spectacular looking event in SDO AIA data yesterday:
As the event progresses, you can clearly see that the material is spiraling around as it slowly moves away from the Sun’s surface. It may be associated with an ejection seen in LASCO C2, although the data here is as yet incomplete. Other users have also shred movies of the same event: here is one shared by danielchangck:
and another movie shared by papavalium:
If you find something interesting, please let us know by either emailing us at firstname.lastname@example.org, or by sharing it on helioviewer.org via YouTube.