STEREO - Solar Terrestrial Relations Observatory
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Important notice about STEREO Behind

Large Filament Eruption

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The twin STEREO spacecraft, now almost 120 degrees apart, captured this large and dramatic prominence eruption over a 30-hour period (Sept. 26-27, 2009). Prominences, called filaments when they are viewed against the surface of the Sun, are clouds of cooler gas suspended above the Sun's surface by magnetic fields. This is one of the first times that a prominence has been sufficiently large that both spacecraft have been able to observe it for hours on end. From the "Behind" perspective (on left) the long filament, darker than the Sun's surface, can be seen rising up and then breaking away, spreading out above most of the Sun's surface. As seen from the "Ahead" spacecraft (right), the filament is seen in profile and so is called a prominence. This is one of the most spectacular events that the STEREO mission has observed.

Scientists are interested in observing the profile view (as seen by the "Ahead" spacecraft), as it confirms the model that prominences move from high solar latitudes toward to the Sun's equator. The prominence observed follows the path of the solar magnetic field, which changes form during the 11-year solar cycle. The shape of this prominence is characteristic of the solar minimum which is the quietest solar minimum in a century.


Last Revised: March 19, 2018 15:00:39 UTC
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