Real world comet coincidences with the Sci-fi book Cosmic Swan:
Comet Swan (2020)
Comet Oumuamua (2019)
Comet Borisov (2017)
It is only a coincidence that the first two comets ever known to swing into the Solar from another star system have trajectories from outside the Solar System as described in the Sci-fi book Cosmic Swan a few years ago.
Another coincidence is an actual comet, just discovered, is named, Swan (2020), when the name of the fictional comet in the book is Cosmic Swan.