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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.

A composite of three different images (02 June 1998; 23:40UT). The red and green contours show the locations of the most intense magnetic fields on the solar surface as observed with SOHO/MDI. The yellow image is the TRACE 171Å image, which shows gas at approximately 1 million degrees. The high-arching coronal loops, starting generally at the outer edges of the active region, are roughly 1 million degrees along their entire length. In the interior of the region, however, the 1-million-degree plasma is restricted to the low-lying ``mossy'' emission that largely overlies the strong magnetic fields. Above it, the core of the active-region corona is much hotter, typically 3-5 million degrees, which emits X-rays, shown in blue, as observed with YOHKOH/SXT. The location of the region on the Sun is shown on the clock face in the upper-left corner; the scale is shown in the lower-right corner.
Active-region corona in 195Å Active-region corona in 1600Å
These images were taken by TRACE on 28 June 2000 at 06 UT. Active Region 9046 is shown in the 195Å passband and the 1600Å passband. The image in 195 A represents emission at 1.5 million degrees. The 1600 A image shows emission from the surface temperature at ~5000 degrees up to 100,000 degrees. Courtesy: Dawn Myers.
A rainy day on the Sun
A rainy day on the Sun! This TRACE movie, taken on 30 June 2000, from 15UT to 16:30UT in the 195Å passband (1.5 million degrees) shows coronal loops cooling rapidly. The loops are initially at a temperature of around 3 million degrees, when they are not visible to TRACE. As they cool, the become bright at the TRACE wavelength; as their temperature drops below 1 million degrees, they rapidly fade again. But the material continues to cool: the dark blobs sliding down the loops (known as coronal rain) are so cool (probably well below 100,000 degrees) that enough non-ionized hydrogen exists to cause the EUV light to be extinguished. So very close to another, the temperatures in the corona range over a factor of close to one hundred! Look at the 1.8MB

QuickTime movie

to see the cool material slide down the magnetic field, pulled down by the strong solar gravity.
Prominence seen in 195Å
This image of Active Region 9046 was taken by TRACE in the 195Å passband (showing the emission of 1.5 million degree gas) on 27 June 2000. The image was rotated over 90 degrees, placing North to the left. The region shows an unusual filament/prominence in absorption, with matter being spewed out to the right in downward arcing strands.
Flare & filament eruption in 195Å Flare & filament eruption in 1600Å Post-eruption arcade Post-eruption arcade (illustration)
The two images on the left were taken on 25 June 2000, around 07:37UT (the images were rotated, so that north is to the left). The image on the left shows a filament in the process of being ejected from the Sun, with cool (dark) and hot (bright; around 1.5 million degrees) material at opposite ends of the long, nearly vertical structure. The second image is a 1600Å exposure (logarithmically displayed), characteristic of material of approximately 100,000 degrees. The third images is a 195Å exposure taken 2h 10m later. It shows a rapidly cooling arcade of loops. The geometry is that of a funnel, as illustrated in the rightmost panel: the loops near the front are higher than those behind it, creating the impression of a crossed set of loops. The high brightness at the apparent crossing point is a consequence of many overlapping loops that all contribute to the total intensity because of the transparency of the coronal gas.
Flare collage
A collage of TRACE and SOHO/MDI images of a flare in progress. The flare occurred on 12 November 1999, around 09:10 UT. The images are: top-left, magnetogram; top-right, 1600Å passband; bottom-right, white light; bottom-left, 195Å channel. The red lines in the four panels in the full-resolution image help to identify the features in the successive images: the footpoints of an arcade of loops, faintly glowing in the 195Å image, light up brightly as a ridge in the 1600Å image as energy impacts on the lower domains in the atmosphere; the ridge runs through the middle of the white polarity, presumably outlining different domains of magnetic connectivity.
Quiet-Sun corona Quiet-Sun magnetic field Blended image
These images were taken on 10 June 1998, around 20:45UT. The top image is a 260-second TRACE 171Å-passband exposure (showing gas at around 1 million degrees); the lower image is a SOHO/MDI magnetic map of that region, showing the two opposite polarities in red and green. The third image shows an overlay that shows that the strongest coronal brightenings occur whenever two strong concentrations of magnetic field of opposite polarity are close together.
Small active region Small active region
Two images taken on 8 May 2000 of active region AR 8983, around 00UT. Despite the impressive appearance in the corona (top images, 171Å passband, characteristic of 1 million-degree gas), sometimes little is seen in the photosphere (bottom image, white-light channel, roughly 4,000 to 6,000 degrees); in this case only a few small pores are seen. Courtesy: Dawn Myers.
Sunspot loops
Observation of Active Region 9017, made on 2 June 2000, at 00:00UT. The image is a blend of a 1600Å image (showing the solar surface combined with the transition region seen in CIV, i.e. with temperatures ranging from 4,000 to 100,000 degrees) and a 171Å image (characteristic of 1MK gas). The green image shows the position of a substantial sunspot, and of the surrounding magnetic plage seen in the transition region. The gold image shows the brightest of the coronal loops ending in what appear to be faint brightenings in the umbra of the spot, and the lower ends of the 3-5 million-degree loops terminating in bright patches of ``moss'' that are the top of the conductively dominated transition region.
Demise of a sunspot
Composite of nine white-light images taken by TRACE of the central spot complex in Active Region 1926 that produced three X-class flares on 6 and 7 June 2000 (see earlier TRACE images). The spot, in which two polarities are combined, evolves so that the lower-central umbral region (the darkest part of the spot) contracts, resulting in a flare (visible even in white-light as a faint whisp in the upper right panel). The umbrae open again briefly, then to disappear altogether. Once that process is completed, the spot evolves rapidly into a decaying cluster of small spots and pores. Look at the 0.9MB

QuickTime movie

that shows the evolution from 6 June 2000 at 05UT through 9 June 07UT; the movie has been only crudely aligned, and shows 1% of the available exposures.

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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