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Images of the Sun taken by the
Transition Region and Coronal Explorer

The TRACE images may be used without restrictions in publications of any kind. We appreciate an acknowledgement indicating that the Transition Region and Coronal Explorer, TRACE, is a mission of the Stanford-Lockheed Institute for Space Research, and part of the NASA Small Explorer program. More information on TRACE and other TRACE images can be found here.
AR9373 disk passage
TRACE observed the rotation of Active Region 9373 from limb to limb over a two week period. This this (QuickTime; JPEG/A compressed; 10.7MB) 9-day movie shows much of that disk passage, at half the resolution (the field of view in these 171 Å images is 350,000 km square). The movie shows, on average, on frame every 30 minutes. Whereas the large-scale evolution of the corona is slow enough that much of the geometry of the field is recognizable when stepping from frame to frame, a much higher cadence would be needed to follow the details. When playing the movie at full speed, the corona reveals its true nature: ever-changing and full of surprises.
Whirling filament/prominence
TRACE observed a this filament/prominence coming over the solar limb on 27 November 1999, in its 171Å passband (1 million degrees), as shown in this (QuickTime; JPEG/A compressed; 2.1MB) 1-day movie. The cool material in the filament sloshes back and forth, absorbing the emission from the hot gas behind it. We don't know what causes these motions, or even whether they are true tornadoes, or rather just sliding back and forth as the magnetic field that supports the cool material changes its configuration. For another example, look at this.
Filament activation; fan into spot
TRACE observed a filament activation on 10 February 2000, in its 171Å passband (1 million degrees), shown in this (QuickTime; JPEG/A compressed; 0.9MB) 1/2-hr movie. Part of the filament rises, and much of the material warms up (becoming bright). The the material is seen to spiral into the sunspot in the middle as it falls back towards the solar surface. The field of view of the movie is 109,000 km to a side.
Coronal rain over AR9454
We have shown coronal rain here before: cool material of some 10,000 to 20,000 degrees raining out of the other hot (1-5 million degree) corona. This particular example, observed over Active Region 9454 on 22 May 2001 from 7 to 10 UT (see this [QuickTime; JPEG/A compressed; 3.4MB] 3-hr movie) shows this phenomenon again. Notice how a ``shower'' blowing in from the left (from the north; the image was rotated over 90 degrees) moves in front of the other loops. Its rain then appears dark against the brighter background: the light from the loops in the background is absorbed in the foreground loops, which are themselves less brightly emitting in this hydrogen line (1216Å), causing the rain in front to appear as relatively dark streaks.
AR9462, AR9463 in 171Å
AR9462, AR9463 in Halpha Map: AR9462, AR9463 in 171Å Map: AR9462, AR9463 in Halpha
The image on the left was taken by TRACE on 24 May 2001, around 09:26 UT, in the 171Å (1 million degree) pass band. It shows Active Region 9463 in the south, and the older AR9462 in the north. It is a good example to show the remarkable complexity of the coronal magnetic field. Use the third image from the left as a map: A coronal loop near "A" connects the leading sunspot in AR9463 to a patch of magnetic field in AR9462. This loop passes over a bundle of loops starting near "B". Between the letter "B" and loop "A" you can see cool material crossing the loop bundle. In a movie, many such loops, with moving, cool material are seen to arch over the loop bundle starting at "B". In the corresponding Halpha image from Big Bear Solar Observatory, showing chromospheric material with temperatures around 10,000 degrees, you can see traces of even lower loops that cross over a filament that just shows up in the TRACE image. Then note a very thin loop near "A" in the TRACE image that is almost at right angles to the loop connecting the active regions. In the trailing part of AR9463 there is something similarly complicated: near "C" the loops show an odd kink (is there a magnetic null point nearby?), with a faint loop passing just above "D" at nearly right angles to it. Is the latter going above or below the loops connecting "C" to the trailing polarity in AR9463. And how does the loop you see near "E" fit into this picture?

The coronal magnetic field is clearly very complicated, and loops cross over and under one another in ways that are often not expected at all. Oh, and on top of that, the loop fan coming out of the leading sunspot at "S" is rotating, as other photospheric spots collide with it.

Spray in AR 9454
TRACE observed a small eruption of cool material in Active Region 9454 on 21 May 2001, in its 171Å passband (1 million degrees). The event occurs near the center of the circle in this image (taken at 04:27:08 UT). Its evolution is shown in this (QuickTime; JPEG compressed; 0.7MB) 45-min. movie (03:56-04:41). The small eruption may be caused by a small magnetic region emerging into the existing configuration; it throws cool material (which absorbs the EUV emission from behind it) up to a height of approximately 40,000 km. There it disappears, either because it becomes too tenuous to see, or because it heats up. The motion of the material is puzzling: are we seeing field lines shake back and forth under the stress of the extra material? Or is the bundle of field lines rotating as it relaxes? Or is all this sideways motion but a reflection of the timing close to the surface that determines where material gets to be thrown up? This is another example of a phenomenon seen by TRACE that has never been seen before; more study is needed to understand what is really happening. The field of view of the movie is 44,000 by 71,000 km (zoomed in by a factor of two compared to the usual display).
M1 flare and oscillating loops and something else
TRACE observed an M1 flare in Active Region 9455 on 15 May 2001, around 2 UT, in the 171Å (1 million degrees) pass band. This (Quicktime/JPEG; 6.7MB) movie shows the flare in the upper part of the field of view (640x480 pixels of 375 km each). The images are very ``soft'' and shows the flare overexposed, because there are at least two other very interesting things happening. First, there is another oscillating loop associated with this flare in the middle of the field of view, as well as in loops pointing towards the lower right (southwest). The sample of such events has tripled in the first few months of this year.. Second, prior to the flare, there is a very peculiar event in the lower right corner: fields appear to unwind, and lift cool, dark material while twisting into the higher field.
ARs 8447, 8441 in 1600Å
ARs 8447, 8441 in 171Å during C flare ARs 8447, 8441 in white light

These 3 images were taken on May 3, 2001 at approximately 08:46 UT. The field of view contains Active Regions 8447 and 8441. The (gold) 171Å image shows a small C-class flare in progress in the million-degree corona. The (gray) white-light image shows the solar surface at a temperature of about 5700 Kelvin. The dark areas which appear in both the white-light image and the (red) 1600Å image are sunspots, where the magnetic field is very strong, and the temperature relatively low (approximately 4000 Kelvin). Courtesy: Dawn Myers

Confusing fields
This image was taken by TRACE on 5 April 2001, around 6:22 UT, in the 171Å passband (1 million degrees). It demonstrates very clearly that when you look off the solar disk, the loops stand our very clearly against the dark sky, but there are often so many of them that the result is confusion. Or maybe it is simply beautiful to behold.
Long-duration flare in AR 9433
At about 11:26 UT, a large (M7.8) flare started in Active Region 9433, with an unusual x-ray intensity profile, showing a sharp, intense spike on top of a more gradual change characteristic of long-duration events. The TRACE image (171Å, showing emission from gas around 1 million Kelvin) was taken at 18:37 UT, well into the decay phase of the flare. It shows the central part of the region, with a cooling arcade on the left (west). Notice the curtain of high loops emanating from the northern edge of the region, going up with no indication where they come down (although it may be in the ridge of brightenings on the southern side of the region). The reticulated intensity pattern in the center (the moss) lies below the hotter (3-5 MK) loops that are seen by YOHKOH. Have a look at YOHKOH/SXT data (unfortunately, SXT missed the main part of the flare, showing only the pre-flare and decay phases).

Other TRACE images in this collection: Set 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

See also a collection of images related to the Sun, other cool stars, and solar-terrestrial effects


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