X-ray View of the Solar Cycle

X-ray View of the Solar Cycle

. Dramatic changes in the solar corona are revealed in this four-year montage of images from the Soft X-ray Telescope (SXT) aboard Yokhoh. The 12 images are spaced at 120-day intervals from the time of the satellite’s launch in August 1991, at the maximum phase of the 11-year sunspot cycle (left), to late 1995 near the minimum phase (right). The bright glow of X-rays near activity maximum comes from very hot, million-degree coronal gases that are confined within powerful magnetic fields anchored in sunspots. Near the cycle minimum, the active regions associated with sunspots have almost disappeared, and there is an overall decrease in X-ray brightness by 100 times. (Courtesy of Gregory L. Slater and Gary A, Linford, NASA, ISAS, the Lockheed-Martin Solar and Astrophysics Laboratory, the National Astronomical Observatory of Japan, and the University of Tokyo.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University