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An Active Island Inside a Dark Coronal Hole
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The bright island inside the dark coronal hole looks like it could be an active region but it's not quite large enough. This small region of activity emerged in the center of the coronal hole making it shine brighter than it would anywhere else on the Sun. Coronal holes are regions where the corona is darker and cooler than the surrounding quiet Sun. We usually don't see active regions inside of coronal holes but there is no reason why it couldn't happen. If fact, many coronal holes wouldn't exist without active regions.
Coronal holes can form from the scattered remnants of old active regions. An example of this is given in the 6 July 2015 XPOW where the large coronal
hole (on the right) is supported by the decayed remains of active regions that emerged months earlier.
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(Prepared by Patricia Jibben)
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