4 Ursae Majoris
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 08h 40m 12.8172s |
| Declination | +64° 19′ 40.570″ |
| Apparent magnitude (V) | +4.620 |
| Characteristics | |
| Spectral type | K2 III |
| U−B color index | +1.193 |
| B−V color index | +1.159 |
| Astrometry | |
| Radial velocity (Rv) | +14.62 km/s |
| Proper motion (μ) | RA: −59.861(80) mas/yr Dec.: 26.544(88) mas/yr |
| Parallax (π) | 13.2035±0.1164 mas |
| Distance | 247 ± 2 ly (75.7 ± 0.7 pc) |
| Absolute magnitude (MV) | 0.150 |
| Details | |
| Mass | 1.234 ± 0.15 M☉ |
| Radius | 18.79±0.38 R☉ |
| Luminosity | 112.4±10.0 L☉ |
| Surface gravity (log g) | 1.8 ± 0.15 cgs |
| Temperature | 4336±99 K |
| Metallicity [Fe/H] | -0.25 ± 0.04 dex |
| Rotational velocity (v sin i) | 8 km/s |
| Age | 4.18 ± 1.95 Gyr |
| Other designations | |
| π2 Ursae Majoris, π2 UMa, Pi2 UMa, 4 Ursae Majoris, BD+64°698, FK5 2677, GC 11850, HD 73108, HIP 42527, HR 3403, PPM 16713, SAO 14616 | |
| Database references | |
| SIMBAD | data |
4 Ursae Majoris (sometimes abbreviated 4 UMa) is the Flamsteed designation of a star in the northern circumpolar constellation of Ursa Major. It also bears the Bayer designation of Pi2 Ursae Majoris (Pi2 UMa, π2 Ursae Majoris, π2 UMa) and is traditionally named Muscida. With an apparent visual magnitude of +4.6, this star is visible from suburban or darker skies based upon the Bortle Dark-Sky Scale. From parallax measurements made during the Gaia mission, this star is at a distance of 247 light-years (76 parsecs) from Earth. As of 2011, one extrasolar planet has been confirmed to be orbiting the star.