Epoch J2000.0 Equinox J2000.0
|Right ascension||20h 31m 4.6s|
|Declination||+40° 30′ 57.05″|
|Apparent magnitude (V)||10.45|
|Apparent magnitude (K)||4.466|
|B−V color index||1.68|
|Variable type||candidate LBV|
|Proper motion (μ)||RA: -3.8 mas/yr
Dec.: -2.8 mas/yr
|Absolute magnitude (MV)||-7.66|
|Luminosity (bolometric)||630,000 L☉|
BD+40° 4210, IRAS 20292+4020, PPM 60064, AG+40 2061, 2MASS J20310464+4030568, TYC 3157-679-1
This star, heavily reddened and extinguished by the interstellar dust of the Milky Way and little studied until now, has turned out to be one of the most luminous stars of the Cygnus OB2 association, with an absolute magnitude of -7.66 and a bolometric luminosity more than 600,000 times that of our Sun.
Its location on the Hertzsprung-Russell diagram put it in the same place as quiescent luminous blue variable stars, suggesting it may be a star of that kind; other peculiarities of its spectrum suggest the same too.
BD+40° 4210 is located close in projection (at 4.8 parsecs) to another luminous blue variable candidate, G79.29+0.46; however, unlike the latter which is surrounded by an extensive ring-shaped nebulosity, no nebula has been found around this star.
- 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.
- http://www.sciops.esa.int/SD/ESACFACULTY/docs/seminars/160212_Comeron.pdf In and around the rich association Cygnus OB2