| Cygnus OB9 | |
|---|---|
| Observation data (J2000.0epoch) | |
| Right ascension | 20h 21m 00.0s[1] |
| Declination | 39° 54′ 00″ |
| Distance | 5,000ly |
| Apparent magnitude (V) | 7.7 |
| Physical characteristics | |
| Associations | |
| Constellation | Cygnus |
| See also:Open cluster,List of open clusters | |
Cygnus OB9 is anOB association inCygnus.[2] It is near to theCygnus OB2 association. The region is embedded within a wider one of star formation known asCygnus X, which is one of the most luminous objects in the sky at radio wavelengths. The region is approximately 5,000 light years from Earth in theconstellation of Cygnus.[3]
Although Cygnus OB9 has many O and B type stars, Cygnus OB9 is also hidden behind a massive dust cloud known as theCygnus Rift likeCygnus OB2.
| Star name | Spectral type | MV | Temperature (K) | Mass (M☉) |
|---|---|---|---|---|
| V2245 Cygni (HD 229196) | O5 | −6.19 | 40,862 | 61.6 |
| ALS 11244 | O5If | −5.42 | 38,612 | 40.1 |
| BD+39 4177 | O6.5 | −5.51 | 37,870 | 39.3 |
| HD 229250 | O7 | −5.28 | 36,872 | 33.9 |
| BD+39 4168 | O7 | −5.40 | 36,872 | 37.3 |
| HD 229202 | O8V | −4.66 | 34,877 | 25.0 |
| HD 228929 | B0.5Ib | −5.60 | 22,537 | 20.5 |
| HD 193945 | B0Vnn | −5.11 | 30,110 | 23.8 |
| RIC 13431720 | B1Ia | −5.91 | 19,979 | 20.5 |
| HD 193426 | B9Ia | −6.71 | 10,500 | 15.4 |
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