The Sun in X-rays

The Sun in X-rays

Fig. 4.25 . The bright glow seen in this X-ray image of the Sun is produced by ionized gas at a temperature of a few million kelvin. It shows magnetic coronal loops that thread the corona and hold the hot gas in place. The brightest features are called active regions and correspond to the sites of the most intense magnetic field strength. The Soft X-ray Telescope, abbreviated SXT, aboard the Japanese Yohkoh satellite recorded this image of the Sunís corona on 1 February 1992, near a maximum of the 11-year cycle of solar magnetic activity. Subsequent SXT images, taken about five years later near activity minimum, show a remarkable dimming of the corona when the active regions associated with sunspots have almost disappeared, and the Sunís magnetic field has changed from a complex structure to a simpler configuration. (Courtesy of Gregory L. Slater, Gary A, Linford, and Lawrence Shing, 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