| NGC 3766 | |
|---|---|
 NGC 3766 image taken with the MPG/ESO 1.2-metre telescope at the La Silla Observatory[1] Credit: ESO | |
| Observation data (J2000 epoch) | |
| Right ascension | 11h 36.1m |
| Declination | −61° 37′ |
| Distance | 5.5 kly |
| Apparent magnitude (V) | 5.3 |
| Apparent dimensions (V) | 12.0′ |
| Physical characteristics | |
| Radius | 9.6 ly |
| Easy to view via binoculars or telescope | |
| Other designations | NGC 3766, Caldwell 97, Collinder 248, Melotte 107, Dunlop 289, Lacaille III.7, C1133-613 |
| Associations | |
| Constellation | Centaurus |
NGC 3766 (also known as Caldwell 97) is an open star cluster in the southern constellation Centaurus. It is located in the vast star-forming region known as the Carina molecular cloud, and was discovered by Nicolas Louis de Lacaille during his astrometric survey in 1751–1752. At a distance of about 1745 pc,[2] the cluster subtends a diameter of about 12 minutes of arc.[3]
There are 137 listed stars, but many are likely non-members, with only 36 having accurate photometric data.[4] It has a total apparent magnitude of 5.3 and integrated spectral type of B1.7.[2] NGC 3766 is relatively young, with an estimated age of log (7.160) or 14.4 million years,[3] and is approaching us at 14.8 km/s.[2] This cluster contains eleven Be stars, two red supergiants and four Ap stars.[4]
36 examples of an unusual type of variable star were discovered in the cluster. These fast-rotating pulsating B-type stars vary by only a few hundredths of a magnitude with periods less than half a day. They are main sequence stars, hotter than δ Scuti variables and cooler than slowly pulsating B stars.[5]
