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 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.

Read more about Starspot:  Detection and Measurements, Temperature, Lifetimes, Activity Cycles