Universe Today
"They need a lot of asteroids: they don’t actually say how much, but the number they do give is huge: over a Jupiter mass of them! It’s not clear to me how stable such a swarm could be co-orbital to an actual planet. Part of the reason Jupiter’s Trojan asteroids work as they do is that they don’t really perturb Jupiter. Also, how do you keep a Jupiter mass of material from collapsing or falling into the planet? Also, where would you get a Jupiter mass of rock?!"
"If there is something between us and the star, then proper motion should change our line of sight through it... For the moment, let’s put the hypothetical cloud out at 10,000 AU. Parallax would make it appear to move by about 20 arcseconds, and its orbital motion would move it by about the same amount over 100 years. So if the cloud is 20" across, it could be responsible for the long-term dimming. This would also help explain the 1.96 Kepler year gap between the two dips (although not the lack of dips at 0.98 years): that’s the time it takes our line of sight from Kepler to return to about the same place, with ~1% taken off due to the cloud’s own orbital motion."
