Why do some pulsar planets have designations with a capital letter at the end? The pulsar PSR B1257+12 has three planets. Most triple-planet system have designation foo b, foo c, and foo d. However, I noticed that the three planets of this pulsar (PSR B1257+12) have a designation of A, B, and C as well as b, c, and d. Why did this naming convention deviate from the standard?
I will just cite this from Wikipedia:

On their discovery, the planets were designated PSR 1257+12 A, B, and C, ordered by increasing distance. 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 &quot;b&quot;, in order of discovery, was established. 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 a nutshell, this is the older nomenclature still kept because of historical reasons.