Sunspots are a regions on the "surface" of the sun (the photosphere)
where the temperature is lower than their surroundings.  These low
temperature regions, caused by the sun's magnetism, still glow with an
orange hue characteristic of the 4000-4500 Kelvin temperature at their
centers.  However, they appear dark on a photograph in contrast with
the surrounding 5800-Kelvin yellowish glow of the photosphere.

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