This colorful image is the “spectrum of the chromospheric flare” obtained during a total solar eclipse in the US on August 21 by the ESA team, which observed the event from the city of Casper in Wyoming.
During the eclipse, when the moon obscures the dazzling light of the solar photosphere, astronomers can perform unique measurements, including analysis of the usually invisible red chromospheric shade-the layer of the solar atmosphere directly above the turbulent surface of the photosphere.
Such an image can be obtained with the last and first light of the solar limb right before and after the complete eclipse, which leads to the appearance of a “flash” spectrum, since measurements must be made in a matter of seconds.
At this time, the sun’s radiation can be divided into a spectrum of colors, denoting different chemical elements.
The spectrum of the outburst shown here is formed by the very first solar limb observed after a total eclipse. The exposure time for obtaining this image was exactly 1/30 s. The sun in the eclipse is shown on the left, the spectrum of each point of the “combined” Sun is on the right.
The strongest radiation is associated with hydrogen, including red hydrogen-alpha on the right, and blue and violet on the left. The bright yellow color between them corresponds to helium. This element was first detected in the spectrum of the flare obtained during the total eclipse on August 18, 1868, although this was not explained at that time. Almost three decades later, the element was discovered on Earth, and now it is known that helium is the second most abundant element in the universe after hydrogen.