OU Geminorum
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 26m 10.2464s |
| Declination | +18° 45′ 24.896″ |
| Apparent magnitude (V) | 6.768 |
| Characteristics | |
| Spectral type | K3Vk |
| U−B color index | 0.662 |
| B−V color index | 0.972 |
| Variable type | BY Dra |
| Astrometry | |
| Radial velocity (Rv) | −8.98±0.10 km/s |
| Proper motion (μ) | RA: −124.020±0.097 mas/yr Dec.: −159.335±0.054 mas/yr |
| Parallax (π) | 68.46±0.34 mas |
| Distance | 47.6 ± 0.2 ly (14.61 ± 0.07 pc) |
| Absolute magnitude (MV) | 5.93±0.05 |
| Orbit | |
| Primary | OU Gem Aa |
| Companion | OU Gem Ab |
| Period (P) | 6.991878±0.000004 d |
| Eccentricity (e) | 0.151±0.0024 |
| Periastron epoch (T) | 54900.0719±0.0203 JD |
| Argument of periastron (ω) (secondary) | 77.63±1.09° |
| Semi-amplitude (K1) (primary) | 57.09±0.15 km/s |
| Semi-amplitude (K2) (secondary) | 66.22±0.28 km/s |
| Details | |
| OU Gem Aa | |
| Mass | 0.85 M☉ |
| Radius | 0.81 R☉ |
| Surface gravity (log g) | 4.55 cgs |
| Temperature | 4960 K |
| OU Gem Ab | |
| Mass | 0.71 M☉ |
| Radius | 0.65 R☉ |
| Surface gravity (log g) | 4.65 cgs |
| Temperature | 4390 K |
| Other designations | |
| OU Gem, BD+18 1214, GJ 233, HD 45088, HIP 30630, SAO 95677 | |
| Database references | |
| SIMBAD | data |
OU Geminorum (OU Gem) is a visual binary or possible triple star located in the constellation of Gemini.
The system has an absolute magnitude of 5.93, so at a distance of 48 light years it has an apparent magnitude of 6.77 when viewed from earth. It also has a total proper motion of 0.210"/yr and belongs to the Ursa Major stream.
The system is a much studied BY Draconis variable star with a period of 6.99 days. The primary star has a spectral type of K3Vk. The secondary star in the system has a surface temperature of 4486±50 K and orbits the primary in about seven days.