To expand on @jvanderbot excellent reply, there's "Roche Limit" [1] - region of space close to massive bodies where gravitation gradient will break up the orbit

To expand on @jvanderbot excellent reply, there's "Roche Limit" [1] - region of space close to massive bodies where gravitation gradient will break up the orbiting body. Given that white dwarfs remain in the cool-down phase for trillions of years, any orbiting body's orbit will slowly decay and eventually it ends up inside the Roche limit. [1] https://en.wikipedia.org/wiki/Roche_limit https://en.wikipedia.org/wiki/Roche_limit