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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.

X-class flare
X-class flare
Sunspot image
On 6 June 2000, TRACE observed two X-class flares (the largest, most intense class of solar flares) in Active Region 1926. The image on the top is a composite image taken at 15:00UT showing a combination of the white-light, ultraviolet, and extreme-ultraviolet images. In red, it shows the ultraviolet continuum, which shows the small-scale magnetic fields at the surface as yellow/orange dots; a white-light image was blended in to show the location of the large, dark sunspots. The green-white image is the 171Å image, showing the location of the bright coronal loops. Note that the flare site runs over the middle of the central spot complex (in which two polarities are joined in one structure), and that they reach out toward the lower small spot as well as to a ridge between the polarities running northward from the center.
The central image is a 171Å EUV image taken at 15:10:15UT showing the very bright core (green and blue) of the flaring region, and some very bright loops around it. The structure running from the image center to the top is erupting, forming the start of a large coronal mass ejection. Notice the loop of magnetic field just to the left and below the center of the image; that loop and adjacent loops are uncoiling as they erupt.
The lower image shows, for comparison, an image of the sunspot in AR 9026 at visible wavelengths taken between the X-class flares of 6 and 7 June, 2000. This was taken at the Swedish Vacuum Solar Telescope (SVST) at La Palma at 13:07 UT on 7 June, 2000. The full field of view is about 150 arcseconds. Note the fine double structure seen in the "light bridge" across the dark umbra that can be seen on this enlarged image. The image was taken with a G-band filter (4305A) and using the adaptive optics system ( http://www.astro.su.se/~rouppe/ao/ao.html ) at the SVST. It has not been processed or filtered, only rotated so that it has the same orientation as the TRACE images with north pointing upward. The observatory (http://www.astro.su.se/English/groups/solar/solar.html) is situated within the Spanish-International Observatory on the Roque de los Muchachos.
There is much more information on this flare (including movies) on the SOHO pages.
Flare at different temperatures
A solar flare observed at different wavelengths: (left) the 171Å image shows plasma at about 1 million degrees; (center) the 195Å image shows plasma at about 1.5 million degrees but also shows very hot flare material through Fe XXIV lines; (right) the YOHKOH/SXT image (with substantially poorer angular resolution) shows the hot flare plasma with temperatures exceeding about 3 million degrees. This flare was observed around 18:30UT on 27 June 1999. Courtesy: Kathy Reeves, SAO.
AR9017; corona
AR9017; photosphere AR9017; transition region
These three images of Active Region 9017 were taken at 14:01 UT on June 2, 2000. These images show 3 different temperature regimes of the solar atmosphere. The 171Å image (gold) shows the million-degree corona. One can see various sets of loops that connect the two sunspots which are visible in the white-light image (yellow) as well as the 1600 image (red). The white-light image (yellow) shows the solar surface (the photosphere) and is at a temperature of about 6000 Kelvin. The sunspots which are regions of the surface with large, concentrated magnetic fields, have a temperature of about 4000 Kelvin. Courtesy: Dawn Myers.
Transition region
These images, taken around 13:05UT on 29 May 2000, show the transition region (left; at temperatures around 100,000 degrees, mixed with photospheric light emitted by gas around 6,000 degrees; observed in the 1600Å passband of TRACE) and the corona (right; 171Å passband; 1 million degrees). Note that the long loops on the righthand side appear to end in the sunspot. Closer inspection shows, however, that the spot is a composite, with faint light bridges separating several dark umbrae. The loops end on or very near these light bridges. Coronal loops
Coronal loops
Loops in the solar corona (such as those on the left observed in the 171Å passband of TRACE - sensitive to gas of one million degrees - on 27 May 2000, around 14:41UT) frequently undergo rapid cooling as the heating stops. The material cools down by conduction to the surface and by radiation. Within some tens of minutes, the temperature drops from a few million degrees to somewhere between 10,000 and 100,000 degrees. The material than falls down towards the surface, sometimes in a stream, sometimes in clumps, following the magnetic field in which it is confined. The false-color image on the right is taken in the 1216Å, or Lyman alpha, channel, which is most sensitive to material of 10,000 to 30,000 degrees, but shows gas up to 100,000 degrees. The falling material shows up only off the disk in faint loops that are only a few percent of the brightness of the disk itself; on the disk, such loops would not be observable against the continuum emission from the solar surface that is also observed in that passband. Cooling loops
Coronal field
A combination of two images taken by TRACE on 7 March 2000, around 00:25UT. The yellow image shows the 195Å passband, or plasma at approximately 1.5 million degrees. The purplish image shows the brightest structures in the 1600Å passband, which shows the location of magnetic field, with the exception of the spots and small pores, which are dark at that wavelength. What makes this image peculiar is the loop configuration in the red circle in the full-sized image: coronal loops have their footpoints on a ridge running right through the middle of a supergranular convection cell where there is hardly any strong field either in bright faculae or in dark pores.
Solar eruption
Solar eruption

On May 19, 1998 (around 08:06 UT for the lefthand image) TRACE observed a massive surge of material lifted from the solar surface to a height of approximately 150,000 km. The material seen in these images is approximately 10,000 to 20,000 degrees. The composite shows images taken at 7:50, 8:02, 8:06, 8:15, 8:25, 8:37 UT, respectively. There is also a rotated version of the single image; and a postscript version of the composite image.

Deep quiet-Sun exposure
This 263-second exposure of the corona over the quiet Sun shows the complexity of the corona. The image was taken in the TRACE 171Å pass band, characteristic of plasma at 1 MK, near the center of the solar disk, on June 10, 1998, at 20:40 UT. The dark edges are caused by vignetting within the telescope. The field of view is 1024x1024 pixels, of 375 km each.
Solar flare (171Å/MDI)
This solar flare was observed by TRACE around 11 UT 17 March 2000. The bottom image on the right is the magnetogram (with red and green showing the two opposite polarities of the magnetic field). The top image shows the hot corona as seen in the TRACE 171Å passband. North of the center of the image, a peculiar spider-like configuration connects the polarities in a most unusual manner; the image on the left shows half the field of view enlarged, with the 171Å-image and the magnetogram faded on top of each other. We do not know what is happening here: only minutes before this frame, mostly east-west orientied loops are visible, and in the next frame most loops run north-south. This intermediate configuration may be a transition state between the two. Notice the bright ``moss'' ridges towards the north, which overlie a ridge of green (normally shown in black) polarity. Solar flare (171Å) Magnetic field)
Wrapped loops
Sometimes TRACE observes coronal loops that are wrapped around eachother (generally once, rarely more). This image, taken on 4 April 2000, at 18:32UT (171Å; 1 million degrees) shows an example of low-lying wrapped loops in AR8939. These loops form part of a small filament complex, with hot loops lighting up briefly as they evolve, wrapped around the generally much cooler loops of the active-region filament. The field of view is 280,000 km to a side; the zoomed-in field is a square with sides of 46,000 km.

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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