Nomenclature for stars discovered before VIIth Catalogue (incl Annex)
All WR identifications up to 7th Catalogue/Annex remain unchanged since
many are in widespread usage in the literature (e.g. WR20, WR20a).
Nomenclature for stars discovered after VIIth Catalogue (incl Annex)
All subsequent discoveries are switched from alphabetical (WRXXa,
b) to numerical (WRXX-1, -2) identification, sorted by year/month of
discovery, in RA order if multiple discoveries arise from a single
source. By way of example, three WR stars have been discovered
since 2006 between the RAs of WR20 and WR21. The first (discovered by
Mauerhan et al. 2011) is assigned WR20-1, while two further discoveries
(from Roman-Lopez et al. 2011) are assigned WR20-2 and -3 (RA ordered).
Since a few journal papers have referred to recently discovered
stars using the former alphabetical scheme it is intended to retain such
aliases for discoveries up to the end of 2012 (WR20aa for WR20-2, WR20c
for WR20-3), but recommend adoption of the numerical scheme in the
literature in the future.
Multiple WR stars identified within a single source are indicated with CAPITAL letters (e.g. WR43a, b, c -> WR43A, B, C).
Recommendations submitted to OC for IAU Working Group for Massive Stars in Dec 2012
Paul Crowther, Wolf-Rainer Hamann, Ian Howarth, Karel van der Hucht, Gregor Rauw. Scheme implemented in Appendix A of Rosslowe & Crowther (2015)