Gather Information: Items of Power - Comet - 16

Specific Items related to the twin-tailed comet so far as is known seem only to be connected second-hand. Many examples can be found across multiple cultures of iconography being engraved or emblazoned on magical items, and weapons.
After seeing the symbol within manuscripts and texts, you realize that this symbol adorned the fibula(brooch) on the cloak of the Sigmarite Templar of the Knights of the Fiery Heart, Aldred Keppler. You understand that throughout most of the Empire, the Cult of Sigmar holds sway as the official religion.
In addition to this, the quillon of the Sword Karaghul, currently in the possession of Felix Jaeger, and it's sister sword Karaghala, currently in the posetion of Goldareas, both have this as a central piece, with the "tails" of the commet helping form the fiery crossguard.

As far as your research shows, the only well-known connections to cosmic influences on the face of Harmwah would be the The Great Vortex of Caledor Dragontamer on the Isle of the Dead in the center of Ulthuan, and the polar Chaos Gates with their direct connection to the second moon of Morrslieb.