56 Persei
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 04h 24m 37.46102s |
| Declination | +33° 57′ 35.2908″ |
| Apparent magnitude (V) | 5.77 (5.80 + 15.00 + 9.16 + 11.30) |
| Characteristics | |
| Spectral type | F4V + DA3.1 + F4 + ? |
| B−V color index | 0.400±0.019 |
| Astrometry | |
| Radial velocity (Rv) | −31.8±2.9 km/s |
| Proper motion (μ) | RA: +43.818 mas/yr Dec.: −90.502 mas/yr |
| Parallax (π) | 23.5093±0.0909 mas |
| Distance | 138.7 ± 0.5 ly (42.5 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.73 |
| Details | |
| 56 Per Aa | |
| Mass | 1.53 M☉ |
| Radius | 1.97+0.05 −0.11 R☉ |
| Luminosity | 7.166±0.034 L☉ |
| Surface gravity (log g) | 4.32±0.14 cgs |
| Temperature | 6,629±225 K |
| Metallicity [Fe/H] | −0.11±0.08 dex |
| Age | 1.811 Gyr |
| 56 Per Ab | |
| Mass | 0.90±0.12 M☉ |
| Surface gravity (log g) | 8.46±0.2 cgs |
| Temperature | 16,420±420 K |
| Other designations | |
| 56 Per, BD+33° 854, HD 27786, HIP 20591, HR 1379, SAO 57216 | |
| Database references | |
| SIMBAD | data |
56 Persei is at least a triple star and possibly a quadruple star system in the northern constellation of Perseus. It is visible to the naked eye as a dim point of light with a combined apparent visual magnitude of 5.77. The system is located 139 light-years (42.5 pc) distant from the Sun based on parallax, but is drifting closer with a radial velocity of −32 km/s.
The main component is a binary system with an orbital period of 47.3 years and a semimajor axis of 17.60 AU. The primary, designated component Aa, is an F-type main-sequence star with a stellar classification of F4V, a star that is currently fusing its core hydrogen. It is 1.8 billion years old with 1.5 times the mass of the Sun and twice the Sun's radius. It is radiating 7 times the luminosity of the Sun from its photosphere at an effective temperature of 6,629 K.
The companion, component Ab, is a hydrogen–rich white dwarf star with a class of DA3.1, having begun its main sequence life with more mass than the current primary and thus evolved into a compact star more rapidly. It now has 90% of the Sun's mass – much higher than the 0.6 M☉ for an average white dwarf – and an effective temperature of 16,420 K; contributing an ultraviolet excess to the system.
Component B shares a common linear motion through space with the primary, and thus may form a third member of the system. This star has 0.84 times the mass of the Sun and a projected separation of 178.2 AU from the primary. The Washington Double Star Catalogue has it classified as a double star, with a magnitude 11.30 companion at an angular separation of 0.60″ along a position angle of 292°, as of 2002.