Cygnus OB9

Cygnus OB9
Observation data (J2000.0 epoch)
Right ascension	20^h 21^m 00.0^s[1]
Declination	39° 54′ 00″
Distance	5000 ly
Apparent magnitude (V)	7.7
Physical characteristics
Associations
Constellation	Cygnus

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

See also

• List of most massive stars

References

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.