Variable Star Designation

Variable Star Designation

Variable stars are designated using a variation on the Bayer designation format of an identifying label (as described below) combined with the Latin genitive of the name of the constellation in which the star lies. See List of constellations for a list of constellations and the genitive forms of their names.

The current naming system is:

• Stars with existing Greek letter Bayer designations are not given new designations.
• Otherwise, start with the letter R and go through Z.
• Continue with RR...RZ, then use SS...SZ, TT...TZ and so on until ZZ.
• Use AA...AZ, BB...BZ, CC...CZ and so on until reaching QZ, omitting J in both the first and second positions.
• Abandon the Latin script after 334 combinations of letters and start naming stars with V335, V336, and so on.

Sample designations are R Coronae Borealis, YZ Ceti, and V603 Aquilae.

Note that the second letter is never further up the alphabet than the first, that is to say no star can be BA, CA, CB, DA or so on.

Most newly discovered variable stars will initially be assigned only a catalog designation by their discovers, hence the "names" OT J155631.0-080440 and SDSS J110014.72+131552.1 for two recently-discovered objects. These stars will eventually receive names in the format described above.