HD 221776
Double star in the constellation of Andromeda
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HD 221776 is a double star in the northern constellation of Andromeda. With an apparent visual magnitude of 6.18,[3] it is viewable by the naked eye user very favourable conditions. The most luminous component has a spectral classification K5III, meaning that it is an orange giant star that has evolved off the main sequence. An infrared excess has been detected around this star, indicating the star is associated with a cloud of dust particles.[9]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda[1] |
| Right ascension | 23h 34m 46.7420s[2] |
| Declination | +38° 01′ 26.402″[2] |
| Apparent magnitude (V) | 6.18[3] |
| Characteristics | |
| Spectral type | K5III[3] |
| U−B color index | +1.97[4] |
| B−V color index | +1.586[3] |
| Astrometry | |
| Radial velocity (Rv) | −13.74±0.11[5] km/s |
| Proper motion (μ) | RA: 10.272±0.114[2] mas/yr Dec.: 11.738±0.106[2] mas/yr |
| Parallax (π) | 4.0297±0.0838 mas[2] |
| Distance | 810 ± 20 ly (248 ± 5 pc) |
| Absolute magnitude (MV) | −0.68[3] |
| Details | |
| Mass | 1.13[6] M☉ |
| Radius | 49[7] R☉ |
| Luminosity | 591[7] L☉ |
| Surface gravity (log g) | 1.61[6] cgs |
| Temperature | 4,103[6] K |
| Metallicity [Fe/H] | −0.04[6] dex |
| Rotational velocity (v sin i) | 2.9[8] km/s |
| Other designations | |
| BD+37°4866, HD 221776, HIP 116365, HR 8950, SAO 73351 | |
| Database references | |
| SIMBAD | A |
| B | |
There is a magnitude 11.8 companion at angular separation of 19.8″ along a position angle of 329°, as of 2002;[10] however, its distance measured by parallax yields a much greater distance than the primary star.[11]
