Kirk wrote: I'm not finding the article I read earlier. However it explained the dips in that star's brightness without resorting to aliens. If the star has an extremely fast rotational period, it will be significantly oblate. The point being an oblate sphere will not have a constant brightness when viewed from different angles. If from Earth we view that star from an angle where the polar region and the equatorial region alternately pass through our view, then the brightness will vary periodically over time.
Sure. As I wrote in the post above yours: while the variable brightness of the star's surface due to its oblateness can explain the asymmetry of the lower left graph and partially explain the variability of the lower right graph, there is still no explanation for the intensity of those drops in brightness.
Something just occurred to me: what if what we are seeing is a pairing of a mostly "clean" black hole and the star, at least for the lower left graph? The black hole would have to be mostly clean--meaning that there isn't much of an accretion disk around it because that disk itself would be glowing and adding to the star's overall brightness--and would likely be some considerable distance from the star so that the black hole isn't actively stealing matter from the star. So the black hole passes between us and the star and the gravitational lensing of the black hole redirected about 15% of the star's light away from us. Perhaps a spectrographic analysis of the light being emitted by the star during another passage (as opposed to just the brightness) could reveal this. Of course an orbit of just one billion miles--about 10% larger than Saturn's orbit around our Sun--means we would have to wait around 35 years for the next passage.
And even THAT wouldn't explain the lower right graph.