Friday, September 28, 2012

Fall 2012 Eclipse Season Ends Tomorrow

The Fall 2012 SDO eclipse season ends tomorrow. Here is a look at the penultimate eclipse in the AIA 1600 bandpass. This wavelength of light is absorbed by the Schumann-Runge continuum of molecular oxygen at an altitude of about 110 km. This creates atomic oxygen, which moves upwards and creates the thermosphere. That atomic oxygen also is ionized by solar EUV to create the ionosphere.
At this wavelength the Sun looks like a ball with a thin, lacy network, bright active regions, and dark sunspots. Many of these features are a little above the visible surface of the Sun. They are held up by the solar magnetic fields. Welcome to the chromosphere, a layer of the solar atmosphere that will be studied by the Iris satellite. The people at LMSAL who built AIA and HMI are building Iris and hope to launch it in January.