| |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Vulpecula |
| Right ascension | 19h36m 37.7281s[2] |
| Declination | 20° 19′ 58.5692″[2] |
| Apparent magnitude (V) | 6.73 - 7.54[3] |
| Characteristics | |
| Spectral type | F6Iab-G2[4] |
| Variable type | δ Cep[3] |
| Astrometry | |
| Proper motion (μ) | RA: 0.906±0.050[2] mas/yr Dec.: −0.960±0.062[2] mas/yr |
| Parallax (π) | 1.0530 ± 0.0390 mas[2] |
| Distance | 3,100 ± 100 ly (950 ± 40 pc) |
| Absolute magnitude (MV) | -3.69[5] |
| Orbit[6] | |
| Period (P) | 2,510 days |
| Eccentricity (e) | 0.675 |
| Periastron epoch (T) | 2444800 |
| Argument of periastron (ω) (secondary) | 353° |
| Semi-amplitude (K1) (primary) | 3.64 km/s |
| Details | |
| Mass | 6.5[7] M☉ |
| Radius | 60[7] R☉ |
| Surface gravity (log g) | 1.75 - 1.85[8] cgs |
| Temperature | 5,655 - 5,965[8] K |
| Metallicity [Fe/H] | 0.09[9] dex |
| Age | 82[9] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
U Vulpeculae is a variable and binary star in the constellation Vulpecula.
It is a classical Cepheid variable and its apparent magnitude ranges from 6.73 to 7.54 over a precise cycle of 7.99 days.[4] Its variable nature was discovered in 1898 at Potsdam ObservatorybyGustav Müller and Paul Kempf.[11]
In 1991 a study of radial velocities showed that it U Vulpeculae is a spectroscopic binary and a full orbit with a period of 2510 days (6.9 years) was first calculated in 1996.[12][7] The secondary star is invisible and is only known from its effect on the motion of the primary.[6]
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