STARSPOT
Starspot
Starspots are equivalent to sunspots but located on other stars. Spots the size of sunspots are very hard to detect since they are too small to cause detectable fluctuations in brightness. Observed starspots are in general much larger than those on the Sun: up to about 30% of the stellar surface may be covered, corresponding to sizes 100 times greater than those on the Sun.The above text is a snippet from Wikipedia: Starspot
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