A question about star names... E.G. CW Tauri, DZ Bootis, IQ Lupi, EU Eridani Take the following examples of star names/identifications:-

Regulus is the common name for a star.

HIP49669 is the Hipparcos ID for the star

HD87901 is the Henry Daper ID for the star

32 Leonis is the Flamsteed ID for the star

Alpha Leonis is the Bayer ID for the star

And now for a probably unrelated stars at random.

Why and how does stars like 'CW Tauri', 'DZ Bootis', 'IQ Lupi', 'EU Eridani' get their name, is there a catalogue for them?  Who assigns their name? Do they individually mean something or randomly chosen letters?  I'm not just after those stars but all stars with similar style naming.

Thanks in advance
The Bayer catalogue uses Greek letters, then lower case Latin letters and if needed, upper case letters. But it never gets beyond "Q"

In 1855, the German astronomer Argelander proposed naming a particular variable star "R" (as using upper case letters at the end of the alphabet would avoid clashing with the Bayer catalogue.

In 1867 it was agreed by the German astronomical society to name variable stars R,S,T... Z, then RR, RS, RT up to ZZ, followed by the constellation name.

This system provided enough names until 1907, when they reached ZZ Cygni.  It was decided to start again with AA, up to AZ, Then BB to BZ etc.  That system provides 344 names and worked only until 1929, and after that, when more variables than this were found in a single constellation, they switched to a 'Vxyz " where "xyz" is a number starting with 345 e.g. V345 Cyg.

So the "2-letter designation" is particular to variable stars http://cdsarc.u-strasbg.fr/afoev/var/edenom.htx and is used in the General Catalogue of Variable stars, but the scheme doesn't originate in the at Catalogue.