2 Persei
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 01h 52m 09.3723s |
| Declination | +50° 47′ 34.054″ |
| Apparent magnitude (V) | 5.70 |
| Characteristics | |
| Spectral type | B9pHgMn |
| B−V color index | −0.067±0.004 |
| Astrometry | |
| Radial velocity (Rv) | 11.4±0.2 km/s |
| Proper motion (μ) | RA: +17.532 mas/yr Dec.: −29.090 mas/yr |
| Parallax (π) | 6.8219±0.1092 mas |
| Distance | 478 ± 8 ly (147 ± 2 pc) |
| Absolute magnitude (MV) | −0.14 |
| Orbit | |
| Primary | 2 Persei A |
| Companion | 2 Persei B |
| Period (P) | 5.62698±0.00002 d |
| Eccentricity (e) | 0.024±0.011 |
| Periastron epoch (T) | 2440281.3±0.4 JD |
| Argument of periastron (ω) (primary) | 208±24° |
| Semi-amplitude (K1) (primary) | 26.5±0.3 km/s |
| Details | |
| Mass | 3.2 M☉ |
| Radius | 3.7 R☉ |
| Luminosity | 156 L☉ |
| Surface gravity (log g) | 3.74 cgs |
| Temperature | 11,218 K |
| Metallicity [Fe/H] | −0.74 dex |
| Rotational velocity (v sin i) | 25 km/s |
| Age | 233 Myr |
| Other designations | |
| BD+50°379, FK5 1052, HD 11291, HIP 8714, HR 536, SAO 22696 | |
| Database references | |
| SIMBAD | data |
2 Persei is a binary star system in the northern constellation Perseus, located around 500 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 is 5.70. The system is moving further away from the Earth with a heliocentric radial velocity of 11 km/s.
In 1970 radial velocity measurements from spectrograms taken at David Dunlap Observatory indicated it was a single-lined spectroscopic binary. Follow up observations led to the determination that it had a nearly circular orbit with a period of 5.6 days. The visible component is a chemically peculiar mercury-manganese star with a stellar classification of B9pHgMn. Other analyses of its spectrum have assigned it the giant star spectral type of B9III.