Which official IAU name belongs to the pulsar planet PSR B1257+12 c?

The official IAU name for pulsar planet PSR B1257+12 c is Poltergeist.

PSR B1257+12 c is also designated PSR B1257+12 B because the original planet-letter system used uppercase letters in some pulsar-planet designations. That naming difference causes frequent confusion: the lowercase “c” and uppercase “B” refer to the same world, not two separate planets.

The planet orbits the millisecond pulsar PSR B1257+12, officially named Lich, about 2,300 light-years away in Virgo. It was detected through pulsar timing—the measurement of tiny, regular changes in the arrival times of the pulsar’s radio pulses. Its orbit lasts roughly 66.5 days, and its mass is more than four times Earth’s.

The IAU approved the name Poltergeist through the 2015 NameExoWorlds campaign. The neighboring planets have the names Draugr and Phobetor, which explains the tempting wrong options: Draugr is PSR B1257+12 b, while Phobetor is PSR B1257+12 d.