Cygnus OB9

Cygnus OB9
Observation data (J2000.0 epoch)
Right ascension20h 21m 00.0s[1]
Declination39° 54′ 00″
Distance5000 ly
Apparent magnitude (V)7.7
Physical characteristics
Associations
ConstellationCygnus
See also: Open cluster, List of open clusters

Cygnus OB9 is an OB association in Cygnus.[2] It is near to the Cygnus OB2 association. The region is embedded within a wider one of star formation known as Cygnus X, which is one of the most luminous objects in the sky at radio wavelengths. The region is approximately 5000 light years from Earth in the constellation 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 the Cygnus Rift like Cygnus OB2.

Prominent stars[4]
Star name Spectral type Luminosity(L☉) Temperature(K) Mass(M☉)
V2245 Cygni (HD 229196) O5 255900 40862 61.6
ALS 11244 O5If 125900 38612 40.1
BD+39 4177 O6.5 136800 37870 39.3
HD 229250 O7 110700 36872 33.9
BD+39 4168 O7 123600 36872 37.3
HD 229202 O8V 62500 34877 25
  1. ^ "Ass Cyg OB 9". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-02.
  2. ^ Pickett, Daniel Edward (1993). "Photoelectric UBV photometry of Cygnus OB3 and Cygnus OB9". ProQuest Dissertations and Theses; Thesis (M.S.)--University of Montana. 52–03: 39. Bibcode:1993PhDT.......160P.
  3. ^ Zakirov, M. M.; Eshankulova, M. U. (2008). "Close binary systems in regions of OB associations. VI. V498 Cyg in Cyg OB9". Kinematics and Physics of Celestial Bodies. 24 (2): 77–88. Bibcode:2008KPCB...24...77Z. doi:10.3103/S0884591308020037. S2CID 121799853.
  4. ^ Comerón, F.; Pasquali, A. (2012). "New members of the massive stellar population in Cygnus". Astronomy & Astrophysics. 110: 2715. Bibcode:2012A&A...543A.101C. doi:10.1051/0004-6361/201219022.