Or it could be the Pupetteer migration fleet! (yes, Larry Niven did garble a 2n-body Klemperer rosette into a 5-body Kemplerer rosette[1])

[1] https://en.wikipedia.org/wiki/Klemperer_rosette#Misuse_and_m...

Also, this: https://en.wikipedia.org/wiki/The_Three-Body_Problem

Yup, as soon as I saw the title I thought of Nightfall - probably my all-time favourite Asimov story :)