51 Andromedae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 01h 37m 59.56074s |
| Declination | +48° 37′ 41.5798″ |
| Apparent magnitude (V) | 3.57 |
| Characteristics | |
| Spectral type | K3- III CN0.5 |
| U−B color index | +1.44 |
| B−V color index | +1.28 |
| Astrometry | |
| Radial velocity (Rv) | 18.41 km/s |
| Proper motion (μ) | RA: +61.334 mas/yr Dec.: -113.100 mas/yr |
| Parallax (π) | 19.2489±0.4077 mas |
| Distance | 169 ± 4 ly (52 ± 1 pc) |
| Absolute magnitude (MV) | −0.04 |
| Details | |
| Mass | 1.75±0.15 M☉ |
| Radius | 21.30±0.21 R☉ |
| Luminosity | 142.1±7.6 L☉ |
| Surface gravity (log g) | 2.01 cgs |
| Temperature | 4,316±54 K |
| Metallicity [Fe/H] | 0.07 dex |
| Age | 1.70±0.40 Gyr |
| Other designations | |
| υ Per, 51 And, BD+47°467, HD 9927, HIP 7607, HR 464, SAO 37375, PPM 44238 | |
| Database references | |
| SIMBAD | data |
51 Andromedae, abbreviated 51 And and formally named Nembus /ˈnɛmbəs/, is the 5th brightest star in the northern constellation of Andromeda, very slightly dimmer than the Andromeda Galaxy also being of 4th magnitude. It is an orange K-type giant star with an apparent magnitude of +3.57 and is about 169 light-years from the Earth/solar system. It is traditionally depicted as one of the two northern, far upper ends of the mythological, chained-to-the-rocks princess, the other being binary star system Gamma Andromedae.
At an estimated age of 1.7 billion years, this is an evolved red giant star with a stellar classification of K3- III CN0.5. The suffix notation indicates a mild enhancement of cyanogen absorption lines in its spectrum. This star has 1.8 times the mass of the Sun and it has expanded to 21.3 times the Sun's radius. It is radiating 142 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,951 K.