50 Cassiopeiae is a white star in the northern constellation of Cassiopeia. In the past, it had been misidentified as a suspected nebula, and given the number NGC 771.[9] The star is visible to the naked eye, having an apparent visual magnitude of +3.95.[2] Based upon an annual parallax shift of 20.76 mas, it is located 157 light years away. It is moving closer, having a heliocentric radial velocity of −18 km/s,[4] and will approach to within 82 ly in 1.879 million years.[2]
 50 Cassiopeiae in optical light | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 02h 03m 26.10206s[1] |
| Declination | +72° 25′ 16.6376″[1] |
| Apparent magnitude (V) | +3.95[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A2 V[3] |
| B−V color index | −0.002±0.007[2] |
| Astrometry | |
| Radial velocity (Rv) | −18.2±0.9[4] km/s |
| Proper motion (μ) | RA: −43.57[5] mas/yr Dec.: +22.30[5] mas/yr |
| Parallax (π) | 20.76 ± 0.14 mas[5] |
| Distance | 157 ± 1 ly (48.2 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.54[2] |
| Details | |
| Mass | 2.56±0.03[3] M☉ |
| Radius | 2.5[6] R☉ |
| Luminosity | 63.8+3.5 −6.4[3] L☉ |
| Temperature | 9,376+240 −235[3] K |
| Metallicity [Fe/H] | +0.18±0.28[7] dex |
| Rotational velocity (v sin i) | 91[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
It is an A-type main-sequence star with a stellar classification of A2 V.[3] It is a suspected variable star with a very small amplitude.[11] 50 Cas has an estimated 2.56 times the mass of the Sun,[3] and about 2.5 times the Sun's radius.[6] It is radiating 64 times the Sun's luminosity from its photosphere at an effective temperature of around 9,376 K.[3]
The star was the brightest star in the occasionally used 1775 to 19th century constellation Custos Messium, typically drawn as a depiction of Charles Messier standing on top of the giraffe (Camelopardus), between Cepheus and Cassiopeia.[12]
References
External links
- "DOCdb page for 50 Cas". Retrieved 2016-12-09.