National Astronomical Observatory of Japan

The Quiet Photosphere and Active Chromosphere


This movie taken by the solar observing satellite HINODE, compares the photosphere, the surface of the Sun (blue color), and the chromosphere (orange color) above it. In the chromosphere we can see vigorous phenomena completely different from the calm photosphere. This movie captures in detail the appearance of the frequent flashes generated due to strong magnetic fields around the periphery of the sunspot, and the plasma erupted dynamically into the upper atmosphere by these flashes. HINODE gives us valuable data which allow us to conduct investigations of such active phenomena caused by magnetic fields.

HINODE opened a new Era in observations of the solar chromosphere

Almost all of the sunlight we see is emitted by the photosphere, a thin layer with a temperature of about 6,000 Kelvin. Outside of the photosphere exists the chromosphere with a temperature on the order of 10,000 Kelvin. But because the light coming from this layer is very weak, it can only be seen during a total solar eclipse. By observing in spectral lines which respond to the chromosphere, HINODE revealed the appearance of an active chromosphere completely different from the quiet photosphere. The phenomena gushing plasma (jets) which occur frequently around the sunspot draw the eye. HINODE clearly captured the scene as, within only a couple of minutes, plasma is dynamically erupted up to a height of over 20,000 km, in other words several times the size of the Earth. Even in locations other than sunspots, fine jets thousands of kilometers long and on the order of 300 kilometers wide occur frequently over the entire surface of the Sun. Ground based telescopes are affected by scintillation in Earth’s atmosphere, making it very difficult for them to capture these minute and transient jet phenomena. These observational results provided by HINODE demonstrate that the chromosphere is a layer of the solar atmosphere heated by countless erupting jets.

Text by: Yukio Katsukawa (Hinode Science Center)
Translation by: Ramsey Lundock (NAOJ)