1 Persei
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 01h 51m 59.32008s |
| Declination | +55° 08′ 50.5837″ |
| Apparent magnitude (V) | 5.49 - 5.74 - 5.85 |
| Characteristics | |
| Spectral type | B1.5V |
| Variable type | eclipsing binary |
| Astrometry | |
| Proper motion (μ) | RA: 12.716(74) mas/yr Dec.: −8.410(79) mas/yr |
| Parallax (π) | 2.6944±0.0888 mas |
| Distance | 1,210 ± 40 ly (370 ± 10 pc) |
| Absolute magnitude (MV) | −1.37/−1.77 |
| Orbit | |
| Primary | 1 Persei A |
| Companion | 1 Persei B |
| Period (P) | 25.935951±0.000003 d |
| Eccentricity (e) | 0.3768±0.0014 |
| Inclination (i) | 88.048±0.002° |
| Periastron epoch (T) | 2443563.466±0.005 HJD |
| Argument of periastron (ω) (secondary) | 109.83±0.10° |
| Semi-amplitude (K1) (primary) | 97.4±0.1 km/s |
| Semi-amplitude (K2) (secondary) | 91.2±0.1 km/s |
| Details | |
| Primary | |
| Mass | 6.95 M☉ |
| Radius | 3.29 R☉ |
| Luminosity | 2,188 L☉ |
| Surface gravity (log g) | 4.25 cgs |
| Temperature | 21,500 K |
| Rotation | 1.45 days |
| Rotational velocity (v sin i) | 115 km/s |
| Secondary | |
| Mass | 7.42 M☉ |
| Radius | 3.86 R☉ |
| Luminosity | 3,311 L☉ |
| Surface gravity (log g) | 4.14 cgs |
| Temperature | 22,000 K |
| Rotation | 1.40 days |
| Rotational velocity (v sin i) | 140 km/s |
| Other designations | |
| V436 Persei, BD+54 396, HD 11241, HIP 8704, HR 533, SAO 22690 | |
| Database references | |
| SIMBAD | data |
1 Persei (1 Per) is an eclipsing binary star in the constellation Perseus. Its uneclipsed apparent magnitude is 5.49. The binary star consists of two B2 type main-sequence stars in a 25.9 day eccentric orbit. The stars are surrounded by a faint cloud of gas visible in mid-infrared, although whether they are the origin of the gas or simply passing through it is unclear.