HD 20104
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Camelopardalis |
| A | |
| Right ascension | 03h 17m 31.527s |
| Declination | +65° 39′ 30.11″ |
| Apparent magnitude (V) | 7.05±0.01 |
| B | |
| Right ascension | 03h 17m 31.593s |
| Declination | +65° 39′ 30.26″ |
| Apparent magnitude (V) | 7.39±0.01 |
| Characteristics | |
| A | |
| Spectral type | A2 V |
| U−B color index | +0.06 |
| B−V color index | +0.08 |
| B | |
| Spectral type | A4V |
| Astrometry | |
| Radial velocity (Rv) | −6±2 km/s |
| Proper motion (μ) | RA: −10.54 mas/yr Dec.: +5.84 mas/yr |
| Parallax (π) | 5.92±0.65 mas |
| Distance | approx. 550 ly (approx. 170 pc) |
| Absolute magnitude (MV) | +0.3 |
| Orbit | |
| Primary | HD 20104 A |
| Companion | HD 20104 B |
| Period (P) | 350 yr |
| Semi-major axis (a) | 0.46″ |
| Eccentricity (e) | 0.4 |
| Inclination (i) | 135° |
| Longitude of the node (Ω) | 58° |
| Periastron epoch (T) | 2055.0 |
| Argument of periastron (ω) (secondary) | 100° |
| Details | |
| A | |
| Mass | 2.46 M☉ |
| B | |
| Mass | 2.27 M☉ |
| Other designations | |
| BD+65°338, GC 3893, HD 20104, HIP 15309, HR 967, SAO 12686, ADS 2436, WDS J03175+6540 | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
HD 20104 (HR 967) is a visual binary in the northern circumpolar constellation Camelopardalis. The system has a combined apparent magnitude of 6.41, making it near naked eye visibility. When resolved in a large telescope, HD 20104 appears to be a pair of 7th magnitude A-type main-sequence stars with a separation of about 0.5″. Located approximately 550 light years away, the system is approaching the Sun with a heliocentric radial velocity of −6 km/s.
The system's stars have masses twice that of the Sun and effective temperatures ranging from 8,100 to 8,700 K, typical of stars their type. The primary radiates at 71.3 L☉ − over luminous for its class − and spins with a projected rotational velocity of 159 km/s. HD 20104 has an age of 313 million years.