The Quintuplet cluster is a dense cluster of massive young stars near the Galactic Center (GC). Its name comes from the fact it has five prominent infrared sources residing in it. Along with the Arches cluster it is one of two in the immediate GC region. Due to heavy extinction by dust in the vicinity, it is invisible to optical observation and must be studied in the X-ray, radio, and infrared bands.
Although it does not contain quite such luminous or massive stars as the nearby Arches cluster, it does have the distinction of hosting two of the extremely rare luminous blue variables, the Pistol star and the less well-known FMM 362, and a third just a few parsecs away. It also contains a number of red supergiants, all suggesting a slightly more evolved cluster nearly 4 million years old.
| Q/GMM | LHO | qF/FMM | Other names | Spectral type | Magnitude (KS) | Luminosity (x solar) | Temperature (K) |
|---|---|---|---|---|---|---|---|
| 1 | 75 | 243 | WR 102da | WC9?d | 7.9 | ~150,000 | ~45,000 |
| 2 | 42 | 231 | WR 102dc | WC9d + OB | 6.7 | ~150,000 | ~45,000 |
| 3 | 19 | 211 | WR 102ha | WC8/9d + OB | 7.2 | ~200,000 | ~50,000 |
| 4 | 84 | 251 | WR 102dd | WC9d | 7.8 | ~150,000 | ~45,000 |
| 5 | 115 | 270N | V4646 Sgr | M2 I | 8.6 (var?) | 24,000 | 3,600 |
| 6 | 79 | 250 | WC9d | 9.3 | ~150,000 | ~45,000 | |
| 7 | 7 | 192 | M6 I | 7.6 | 47,000 | 3,274 | |
| 8 | 67 | 240 | WR 102hb | WN9h | 9.6 | 2,600,000 | 25,100 |
| 9 | 102 | 258 | WR 102db | WC9?d | 9.2 | ~200,000 | ~45,000 |
| 10 | 71 | 241 | WR 102ea | WN9h | 8.8 | 2,500,000 | 25,100 |
| 11 | 47 | 235N | WR 102f | WC8 | 10.4 | ~200,000 | ~60,000 |
| 12 | 77 | 278 | O6-8 I eq? | 9.6 | ~1,200,000 | ~35,000 | |
| 13 | 100 | 257 | O6-8 I fe | 9.4 | ~1.400,000 | ~35,000 | |
| 14 | 146 | 307A | O6-8 I f? | 8.7 | ~2,500,000 | ~35,000 | |
| 15 | 110 | 270S | O6-8 I f (Of/WN?) | 10.6 | 1,600,000 | 25,100 | |
| 134 | Pistol Star | LBV | 7.3 | 1,600,000 | 11,800 | ||
| 362 | V4650 Sgr | LBV | 7.1 | 1,800,000 | 11,300 | ||
| 99 | 256 | WR 102i | WN9h | 10.5 | 1,500,000 | 31,600 | |
| 158 | 320 | WR 102d | WN9h | 10.5 | 1,200,000 | 35,100 | |
| G0.120 0.048 | LBV | 7.5 | 1,600,000 - 4,000,000 | ? |
The original five quintuplet members are Q1, Q2, Q3, Q4, and Q9, although Liermann mistakenly describes the red supergiant LHO 115 (=Q5) as one of the original five. Note that these five objects are all extremely hot carbon-type Wolf-Rayet stars rather than the expected cool objects that would be expected to dominate in the infrared. They are all shrouded in dust and were initially mistaken for protostars, but the dust is now thought to be created in colliding stellar winds between the evolved Wolf-Rayet star and a less evolved hot OB companion.
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