BD+40°4210
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 31m 04.659s |
| Declination | +40° 30′ 56.92″ |
| Apparent magnitude (V) | 10.45 |
| Characteristics | |
| Spectral type | B2Ia |
| Apparent magnitude (K) | 4.466 |
| Apparent magnitude (J) | 5.469 |
| Apparent magnitude (H) | 4.833 |
| B−V color index | 1.68 |
| Variable type | candidate cLBV |
| Astrometry | |
| Proper motion (μ) | RA: −3.1731±0.097 mas/yr Dec.: −4.612±0.114 mas/yr |
| Parallax (π) | 0.6530±0.0568 mas |
| Distance | 5,000 ± 400 ly (1,500 ± 100 pc) |
| Absolute magnitude (MV) | −7.66 |
| Details | |
| Mass | 54 M☉ |
| Radius | 55.9 R☉ |
| Luminosity (bolometric) | 630,000 L☉ |
| Temperature | 21,353 K |
| Age | 3.5 Myr |
| Other designations | |
| BD+40°4210, IRAS 20292+4020, 2MASS J20310464+4030568, TYC 3157-679-1, PPM 60064 | |
| Database references | |
| SIMBAD | data |
BD+40°4210 is a hot luminous supergiant star located in the constellation Cygnus. It is a member of the Cygnus OB2 association and a candidate luminous blue variable.