4 Ursae Minoris
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Minor |
| Right ascension | 14h 08m 50.92654s |
| Declination | +77° 32′ 51.0466″ |
| Apparent magnitude (V) | 4.80 |
| Characteristics | |
| Spectral type | K3-IIIb Fe-0.5 |
| B−V color index | 1.368 |
| Astrometry | |
| Radial velocity (Rv) | +5.86±0.10 km/s |
| Proper motion (μ) | RA: −30.45 mas/yr Dec.: +32.85 mas/yr |
| Parallax (π) | 7.14±0.42 mas |
| Distance | 460 ± 30 ly (140 ± 8 pc) |
| Absolute magnitude (MV) | −1.06 |
| Orbit | |
| Period (P) | 605.8 d |
| Semi-major axis (a) | 6.5 mas |
| Eccentricity (e) | 0.137±0.012 |
| Inclination (i) | 136.0±5.1° |
| Longitude of the node (Ω) | 325.5±2.8° |
| Periastron epoch (T) | 2,438,901.7±8.5 JD |
| Argument of periastron (ω) (secondary) | 311.8±5.2° |
| Semi-amplitude (K1) (primary) | 12.65±0.16 km/s |
| Details | |
| 4 UMi A | |
| Radius | 28 R☉ |
| Luminosity | 436.72 L☉ |
| Surface gravity (log g) | 1.73±0.45 cgs |
| Temperature | 4,165±48 K |
| Metallicity [Fe/H] | −0.19±0.11 dex |
| Other designations | |
| 4 UMi, BD+78° 478, FK5 524, HD 124547, HIP 69112, HR 5321, SAO 7958 | |
| Database references | |
| SIMBAD | data |
4 Ursae Minoris is a binary star system in the northern circumpolar constellation Ursa Minor. It is faintly visible to the naked eye with an apparent visual magnitude of 4.80. Based upon an annual parallax shift of 7.14±0.42 mas as seen from Earth's orbit, it is located roughly 460 light years from the Sun. It is moving further away with a heliocentric radial velocity of +5.9 km/s.
This is a single-lined spectroscopic binary star system with an orbital period of 1.66 years and an eccentricity of 0.14. The primary is a red giant of spectral type K3-IIIb Fe-0.5, a star that has used up its core hydrogen and is expanding. The suffix notation indicates the spectrum displays a mild underabundance of iron for a star of its type. It has expanded to around 28 times the Sun's radius and is radiating 437 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,165 K.