Tabby’s Star

It is said to be the weirdest star in our galaxy. It dims up to 20% at random times and for random duration, and no one has any clear idea why. Explanations include swarms of comets and super-structures made by alien life-forms. But the rather obvious explanation that it may be the star itself dimming and brightening doesn't appear on the list. Why not?

If stars are externally powered, as some people believe, then stars in unstable electrical environments will dim and brighten just as observed.

Artist impression of Tabby's star

By NASA/JPL-Caltech - http://photojournal.jpl.nasa.gov/jpeg/PIA20053.jpg, Public Domain, Link