STEREO sees a very unstable solar prominence

January 17, 2010 02:56 by scibuff

The Extreme Ultraviolet Imager (EUVI), one of the five cameras of the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) on the Solar Terrestrial Relations Observatory (STEREO) Behind, captured this very unstable solar prominence visible for almost three days before it disappeared on January 8.  EUVI’s 304 Angstrom bandpass is ideal for capturing solar prominence because it is sensitive to the He II singly ionized state of helium at a characteristic temperature of about 80,000 K – the temperature of prominence material.

Solar prominence captured by the STEREO (behind) spacecraft between January 6 and January 8, 2010 - Credit: NASA/STEREO

A solar prominence is an often loop-shaped bright feature originating from the photosphere extending outwards to Sun’s corona. It contains relatively cool plasma, or ionized gas, which is similar in composition to a thin layer of atmosphere just above the Sun’s surface, know as the chromosphere. Although this material can have a temperature of the order of tens of thousands of degrees (several times hotter than the Sun’s surface), it is bone-chilling cold compared to million degrees of the extremely hot plasma that makes up the solar corona. The mass contained within a prominence is typically of the order of 100 billion tonnes.

In the video above, the cloud of gases seems to swirl and twist in rolling motions, though at times the material can be seen flowing directionally along magnetic field lines back into the Sun. Although prominences occur fairly often, this one exhibited more dynamic motion than most.

STEREO (Solar TErrestrial RElations Observatory) is the third mission in NASA’s Solar Terrestrial Probes program (STP). This two-year mission will employ two nearly identical space-based observatories – one ahead of Earth in its orbit, the other trailing behind – to provide the first-ever stereoscopic measurements to study the Sun and the nature of its coronal mass ejections, or CMEs