2 Vulpeculae
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Vulpecula |
| 2 Vul A | |
| Right ascension | 19h 17m 43.6354s |
| Declination | +23° 01′ 31.9418″ |
| Apparent magnitude (V) | 5.43 |
| 2 Vul B | |
| Right ascension | 19h 17m 43.7343s |
| Declination | +23° 01′ 30.8604″ |
| Characteristics | |
| Spectral type | B1 IV |
| B−V color index | 0.020±0.003 |
| Variable type | β Cep |
| Astrometry | |
| 2 Vul A | |
| Radial velocity (Rv) | +1.0±4.2 km/s |
| Proper motion (μ) | RA: +0.956±0.041 mas/yr Dec.: −6.636±0.087 mas/yr |
| Parallax (π) | 1.8212±0.0880 mas |
| Distance | 1,790 ± 90 ly (550 ± 30 pc) |
| Absolute magnitude (MV) | −2.35 |
| 2 Vul B | |
| Proper motion (μ) | RA: −0.170±0.038 mas/yr Dec.: −5.324±0.073 mas/yr |
| Parallax (π) | 1.7131 ± 0.0757 mas |
| Distance | 1,900 ± 80 ly (580 ± 30 pc) |
| Details | |
| Mass | 12.5±0.6 M☉ |
| Luminosity (bolometric) | 21,922 L☉ |
| Temperature | 26,850 K |
| Metallicity [Fe/H] | −0.06±0.10 dex |
| Rotational velocity (v sin i) | 270 km/s |
| Age | 12.6±0.7 Myr |
| Other designations | |
| 2 Vul, ES Vul, BD+22°3648, HD 180968, HIP 94827, HR 7318, SAO 87036, WDS 19177+2302 | |
| Database references | |
| SIMBAD | data |
2 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located around 1,800 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.43.
2 Vulpeculae is a double-lined spectroscopic binary; as of 2002, the pair had an angular separation of 1.72″ along a position angle of 127.2°.
The primary component of the binary is a rapidly rotating Be star with a stellar classification of B1 IV. It is a variable star with an amplitude of 0.06 magnitude and a period of 0.6096 days, tentatively classified as Beta Cephei variable. The variability was discovered in 1959, and it has been assigned the variable star designation ES Vulpeculae.