PSR B1257+12

They were discovered before the convention that extrasolar planets receive designations consisting of the star's name followed by lower-case Roman letters starting from "b", in order of discovery, was established.

[9] However, they are listed under the latter convention on astronomical databases such as SIMBAD and the Extrasolar Planets Encyclopaedia, with A becoming b, B becoming c, and C becoming d. In July 2014, the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.

[11] In December 2015, the IAU announced the winning names, submitted by the Planetarium Südtirol Alto Adige in Karneid, Italy, were Lich for the pulsar and Draugr, Poltergeist, and Phobetor for planets A, B, and C, respectively:[7][12] In 2016, the IAU organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars (including stellar remnants).

[6] PSR B1257+12 was discovered by the Polish astronomer Aleksander Wolszczan on 9 February 1990 using the Arecibo radio telescope.

In 1992, Wolszczan and Dale Frail published a famous paper on the first confirmed discovery of planets outside the Solar System.

Additional uncertainty surrounded the system, because of a claim of an earlier pulsar planet around PSR 1829-10 that had to be retracted due to errors in calculations.

[21][22][23][24] The dwarf planet hypothesis was also retracted because further observations showed that the pulsation anomalies previously thought to reveal a fourth orbital body are "not periodic and can be fully explained in terms of slow changes in the pulsar's dispersion measure".