"We dug a little deeper to figure out why that star [was repeatedly] getting brighter and fainter, and the simplest explanation is that we're seeing something at [its] surface rotate in and out of view every nine hours," suggesting its rotation rate, Hermes said.
Since LP 40-365 had such a slow rotation rate, Hermes and Putterman think that it is shrapnel from a star that exploded when it had too much mass from its partner when orbiting around each other at a fast pace.