| Observation data EpochJ2000 EquinoxJ2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 02h 53m 42.61284s[1] |
| Declination | +38° 20′ 14.9532″[1] |
| Apparent magnitude (V) | 5.343[2] |
| Characteristics | |
| Spectral type | F6V[3] |
| U−Bcolor index | +0.03[4] |
| B−Vcolor index | +0.42[4] |
| Astrometry | |
| Radial velocity (Rv) | 5.8 ± 2[5] km/s |
| Proper motion (μ) | RA: 46.79[1]mas/yr Dec.: -78.90[1]mas/yr |
| Parallax (π) | 14.15±0.72 mas[1] |
| Distance | 230 ± 10 ly (71 ± 4 pc) |
| Orbit[6] | |
| Period (P) | 31.633 ± 0.024 a (11,553.9 ± 8.7 d) |
| Semi-major axis (a) | 0.2224 ± 0.0011″ |
| Eccentricity (e) | 0.7560 ±0.0023 |
| Inclination (i) | 120.48 ± 0.20° |
| Longitude of the node (Ω) | 26.62 ± 0.24° |
| Periastronepoch (T) | 2450255.5 ± 12 |
| Argument of periastron (ω) (secondary) | 265.54 ± 0.11° |
| Details | |
| 20 Per A | |
| Mass | 1.5[7] M☉ |
| 20 Per A | |
| Mass | 1.5[7] M☉ |
| Other designations | |
| 20 Per,BD+37° 655,HD 17904,HIP 13490,HR 855,SAO 55975,WDS J02537+3820 | |
| Database references | |
| SIMBAD | data |
20 Persei is a visualbinary star in the northernconstellation ofPerseus, a few degrees fromPi Persei. It is visible to the naked eye as a dim, yellow-white hued point of light with a combinedapparent visual magnitude of 5.343.[2] The system is located around 230 light-years (71 pc) away from the Sun, based on itsparallax.[1] It is receding from the Earth with a heliocentricradial velocity of +6 km/s.[5]
The orbit of the two stars has been calculated from the secondary changing its position relative to the primary. The two orbit each other every 31.6 years with an angularsemimajor axis of 0.22 arcseconds and aneccentricity of 0.7560.[6] The combined spectrum of 20 Persei matches that of anF-type main-sequence star,[3] and the two stars are thought to have equal masses, 1.5 times that of the Sun.[7] A ninth-magnitude star, designated 20 Persei C, may be associated with the pair.[8]
