Cygnus OB2
Cygnus OB2 is a large young cluster of stars in the constellation of Cygnus.
The cluster is an OB association. It includes some of the most massive and most luminous stars known. An example is the suspected luminous blue variable Cyg OB2 #12. The cluster also includes one of the largest known stars, NML Cygni.[1]
The region is inside an even larger area of star formation called 'Cygnus X'. This is one of the most luminous objects in the sky at radio wavelengths. The region is about 1,400 parsecs away fron us.[2]
Although it is huge, Cygnus OB2 is hidden behind a massive dust cloud known as the Cygnus Rift. This hides many of the stars. This means that, despite its size, it is hard to see in detail. The estimated number of massive stars range from 50 to 100 of spectral type O.[3] Its total mass is calculated as (4–10)×104 or 3×104 solar masses.[3]
| Name | Radius (Solar radii) | Spectral class |
|---|---|---|
| Cygnus OB2-8A1 | 20 | O6If |
| Cygnus OB2-8A2 | 14.8 | O5.5III |
| Cygnus OB2-12 | 246 | B3-4Ia+ |
| Cygnus OB2-15 | 6.2 | O8V |
| Cygnus OB2-16 | 8.5 | O8V |
| Cygnus OB2-27A | 7.25 | O9.5V |
| Cygnus OB2-27B | 7.16 | B0V |
| Cygnus OB2-37 | 3.61 | B3V |
| WR 147S | 29.8 | WN8h |
| WR 147N | 9.18 | B0.5V |
| NML Cygni | 1,350 | M4.5-M7.9Ia-III |
| BD+40 4210 | 55.9 | B1III:e |
| V1827 Cygni | 32.69 | Ofpe |
| A37 | 12 | O5V |
References
change- ↑ Schuster M.T.; et al. (2009). "Imaging the cool hypergiant NML Cygni's dusty circumstellar envelope with adaptive optics". The Astrophysical Journal. 699 (2): 1423–1432. arXiv:0904.4690. Bibcode:2009ApJ...699.1423S. doi:10.1088/0004-637X/699/2/1423. S2CID 17699562.
- ↑ Rygl K.; et al. (2012). "Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region". Astronomy and Astrophysics. 539: A79. arXiv:1111.7023. Bibcode:2012A&A...539A..79R. doi:10.1051/0004-6361/201118211. S2CID 54647474.
- ↑ 3.0 3.1 Wright N.J.; et al. (2010). "The massive sar-frming rgion Cygnus OB2. II. Integrated sellar poperties and the sar frmation hstory". The Astrophysical Journal. 713 (2): 871–882. arXiv:1003.2463. Bibcode:2010ApJ...713..871W. doi:10.1088/0004-637X/713/2/871. S2CID 118590238.