Inastronomy, avariable-star designation is a unique identifier given tovariable stars. It extends theBayer designation format, with an identifying label (as described below) preceding theLatingenitive of the name of theconstellation in which the star lies. The identifying label can be one or twoLatin letters or aV plus a number (e.g. V399). Examples areR Coronae Borealis,YZ Ceti,V603 Aquilae. (SeeList of constellationsfor a list of constellations and the genitive forms of their names.)
The current naming system is:[1]
| Variable Number | Designation |
|---|---|
| 1 | R |
| 2 | S |
| 3 | T |
| 4 | U |
| 5 | V |
| 6 | W |
| 7 | X |
| 8 | Y |
| 9 | Z |
| 10 | RR |
| 11 | RS |
| 12 | RT |
| 13 | RU |
| 14 | RV |
| 15 | RW |
| 16 | RX |
| 17 | RY |
| 18 | RZ |
| 19 | SS |
| 20 | ST |
| 21 | SU |
| 22 | SV |
| 23 | SW |
| 24 | SX |
| 25 | SY |
| 26 | SZ |
| 27 | TT |
| 28 | TU |
| 29 | TV |
| 30 | TW |
| 31 | TX |
| 32 | TY |
| 33 | TZ |
| 34 | UU |
| 35 | UV |
| 36 | UW |
| 37 | UX |
| 38 | UY |
| 39 | UZ |
| 40 | VV |
| 41 | VW |
| 42 | VX |
| 43 | VY |
| 44 | VZ |
| 45 | WW |
| 46 | WX |
| 47 | WY |
| 48 | WZ |
| 49 | XX |
| 50 | XY |
| 51 | XZ |
| 52 | YY |
| 53 | YZ |
| 54 | ZZ |
| 55 | AA |
| 56 | AB |
| 57 | AC |
| 58 | AD |
| 59 | AE |
| 60 | AF |
| 61 | AG |
| 62 | AH |
| 63 | AI |
| 64 | AK |
| 65 | AL |
| 66 | AM |
| 67 | AN |
| 68 | AO |
| 69 | AP |
| 70 | AQ |
| 71 | AR |
| 72 | AS |
| 73 | AT |
| 74 | AU |
| 75 | AV |
| 76 | AW |
| 77 | AX |
| 78 | AY |
| 79 | AZ |
| 80 | BB |
| 81 | BC |
| 82 | BD |
| 83 | BE |
| 84 | BF |
| 85 | BG |
| 86 | BH |
| 87 | BI |
| 88 | BK |
| 89 | BL |
| 90 | BM |
| 91 | BN |
| 92 | BO |
| 93 | BP |
| 94 | BQ |
| 95 | BR |
| 96 | BS |
| 97 | BT |
| 98 | BU |
| 99 | BV |
| 100 | BW |
| 101 | BX |
| 102 | BY |
| 103 | BZ |
| 104 | CC |
| 105 | CD |
| 106 | CE |
| 107 | CF |
| 108 | CG |
| 109 | CH |
| 110 | CI |
| 111 | CK |
| 112 | CL |
| 113 | CM |
| 114 | CN |
| 115 | CO |
| 116 | CP |
| 117 | CQ |
| 118 | CR |
| 119 | CS |
| 120 | CT |
| 121 | CU |
| 122 | CV |
| 123 | CW |
| 124 | CX |
| 125 | CY |
| 126 | CZ |
| 127 | DD |
| 128 | DE |
| 129 | DF |
| 130 | DG |
| 131 | DH |
| 132 | DI |
| 133 | DK |
| 134 | DL |
| 135 | DM |
| 136 | DN |
| 137 | DO |
| 138 | DP |
| 139 | DQ |
| 140 | DR |
| 141 | DS |
| 142 | DT |
| 143 | DU |
| 144 | DV |
| 145 | DW |
| 146 | DX |
| 147 | DY |
| 148 | DZ |
| 149 | EE |
| 150 | EF |
| 151 | EG |
| 152 | EH |
| 153 | EI |
| 154 | EK |
| 155 | EL |
| 156 | EM |
| 157 | EN |
| 158 | EO |
| 159 | EP |
| 160 | EQ |
| 161 | ER |
| 162 | ES |
| 163 | ET |
| 164 | EU |
| 165 | EV |
| 166 | EW |
| 167 | EX |
| 168 | EY |
| 169 | EZ |
| 170 | FF |
| 171 | FG |
| 172 | FH |
| 173 | FI |
| 174 | FK |
| 175 | FL |
| 176 | FM |
| 177 | FN |
| 178 | FO |
| 179 | FP |
| 180 | FQ |
| 181 | FR |
| 182 | FS |
| 183 | FT |
| 184 | FU |
| 185 | FV |
| 186 | FW |
| 187 | FX |
| 188 | FY |
| 189 | FZ |
| 190 | GG |
| 191 | GH |
| 192 | GI |
| 193 | GK |
| 194 | GL |
| 195 | GM |
| 196 | GN |
| 197 | GO |
| 198 | GP |
| 199 | GQ |
| 200 | GR |
| 201 | GS |
| 202 | GT |
| 203 | GU |
| 204 | GV |
| 205 | GW |
| 206 | GX |
| 207 | GY |
| 208 | GZ |
| 209 | HH |
| 210 | HI |
| 211 | HK |
| 212 | HL |
| 213 | HM |
| 214 | HN |
| 215 | HO |
| 216 | HP |
| 217 | HQ |
| 218 | HR |
| 219 | HS |
| 220 | HT |
| 221 | HU |
| 222 | HV |
| 223 | HW |
| 224 | HX |
| 225 | HY |
| 226 | HZ |
| 227 | II |
| 228 | IK |
| 229 | IL |
| 230 | IM |
| 231 | IN |
| 232 | IO |
| 233 | IP |
| 234 | IQ |
| 235 | IR |
| 236 | IS |
| 237 | IT |
| 238 | IU |
| 239 | IV |
| 240 | IW |
| 241 | IX |
| 242 | IY |
| 243 | IZ |
| 244 | KK |
| 245 | KL |
| 246 | KM |
| 247 | KN |
| 248 | KO |
| 249 | KP |
| 250 | KQ |
| 251 | KR |
| 252 | KS |
| 253 | KT |
| 254 | KU |
| 255 | KV |
| 256 | KW |
| 257 | KX |
| 258 | KY |
| 259 | KZ |
| 260 | LL |
| 261 | LM |
| 262 | LN |
| 263 | LO |
| 264 | LP |
| 265 | LQ |
| 266 | LR |
| 267 | LS |
| 268 | LT |
| 269 | LU |
| 270 | LV |
| 271 | LW |
| 272 | LX |
| 273 | LY |
| 274 | LZ |
| 275 | MM |
| 276 | MN |
| 277 | MO |
| 278 | MP |
| 279 | MQ |
| 280 | MR |
| 281 | MS |
| 282 | MT |
| 283 | MU |
| 284 | MV |
| 285 | MW |
| 286 | MX |
| 287 | MY |
| 288 | MZ |
| 289 | NN |
| 290 | NO |
| 291 | NP |
| 292 | NQ |
| 293 | NR |
| 294 | NS |
| 295 | NT |
| 296 | NU |
| 297 | NV |
| 298 | NW |
| 299 | NX |
| 300 | NY |
| 301 | NZ |
| 302 | OO |
| 303 | OP |
| 304 | OQ |
| 305 | OR |
| 306 | OS |
| 307 | OT |
| 308 | OU |
| 309 | OV |
| 310 | OW |
| 311 | OX |
| 312 | OY |
| 313 | OZ |
| 314 | PP |
| 315 | PQ |
| 316 | PR |
| 317 | PS |
| 318 | PT |
| 319 | PU |
| 320 | PV |
| 321 | PW |
| 322 | PX |
| 323 | PY |
| 324 | PZ |
| 325 | |
| 326 | QR |
| 327 | QS |
| 328 | QT |
| 329 | QU |
| 330 | QV |
| 331 | QW |
| 332 | QX |
| 333 | QY |
| 334 | QZ |
| 335 | V335 |
| 336 | V336 |
| 337 | V337 |
| 338 | V338 |
| - | V339, V340, etc. |
In the early 19th century few variable stars were known, so it seemed reasonable to use the letters of theLatin script. Because very few constellations contained stars with uppercase Latin-letter Bayer designation greater thanQ, the letter R was chosen as a starting point so as to avoid confusion with letter spectral types or the (now rarely used) Latin-letter Bayer designations. AlthoughLacaille had used uppercase R–Z letters in a few cases, for example X Puppis (HR 2548), these designations were either dropped or accepted as variable star designations.[2] The star T Puppis was accepted by Argelander as a variable star and is included in theGeneral Catalogue of Variable Stars with that designation but is now classed as non-variable.[3]
This variable starnaming convention was developed byFriedrich W. Argelander. There is a widespread belief according to which Argelander chose the letter R forGermanrot orFrenchrouge, both meaning "red", because many variable stars known at that time appear red.[4] However, Argelander's own statement disproves this.[5]
By 1836, even the letter S had only been used in one constellation,Serpens. With the advent of photography the number of variables piled up quickly, and variable star names soon fell into the Bayer-trap of reaching the end of the alphabet while still having stars to name.[citation needed] After two subsequent supplementary double-lettering systems hit similar limits, numbers were finally introduced.[5]
In 1865,G. F. Chambers published a catalogue of 123 variables, all but one of which had a variable star designation in the Argelander scheme.[6] The following year,E. Schönfeld published a variable star catalogue with 112 entries; most used the same scheme. This catalogue would not be updated until 1888, whenS. C. Chandler published an update. He released two more updates to this catalogue in 1893 and 1896. TheGerman Astronomical Society then took over the task of maintaining variable star identifiers by publishing annual updates in theAstronomische Nachrichten journal.[7]
As with all categories of astronomical objects, names are now assigned by theInternational Astronomical Union (IAU). Since 1946, the IAU has delegated this task to theSternberg Astronomical Institute and theInstitute of Astronomy of the Russian Academy of Sciences in Moscow, Russia.[7] Sternberg publishes theGeneral Catalog of Variable Stars (GCVS), which is amended approximately once every two years by the publication of a newName-List of Variable Stars.[8] For example, in December 2011, the 80thName-List of Variable Stars, Part II, was released, containing designations for 2,161 recently discovered variable stars, which brought the total number in theGCVS to 45,678 variable stars. Among the newly designated objects were V0654 Aurigae, V1367 Centauri, and BU Coronae Borealis.[9]
International service of variable stars: Naming, classification, identification