Never mind the death of the dinosaurs. Could this be the cause of the possible comet strike in the Northern Hemisphere that destroyed the Clovis culture, killed the large mammals and triggered the thousand year Younger Dryas cooling?
Whatever did all that was close, and not a third of a light year off. A soviet scientist by the name of S. K. Vsehsviatsky (at least in Roman letters) back in the 50s noted that the rapid decrease in short period comets since Roman times indicated a very recent source (within our system) for all of them and Velikovsky claimed that short period comets, volcanism, and earthquakes were all remnant phenomena from recent catastrophes
which had all been damping more or less exponentially since Greco-Roman times .
I don't see any of that as an argument against the existence of this red dwarf Nemesis however and if Nemesis can be shown to exist, we need to get a look at it. One theory about habitable planets says that the most likely places for them would be around red dwarf stars.