  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cepheus [1] |
| Right ascension | 23h 27m 00.91338s [2] |
| Declination | +87° 18′ 27.0304″ [2] |
| Apparent magnitude (V) | 5.56 [1] |
| Characteristics | |
| Spectral type | A8III [3] or A7IV [4] |
| B−V color index | 0.250±0.004 [1] |
| Astrometry | |
| Radial velocity (Rv) | −10.9±2.9 [1] km/s |
| Proper motion (μ) | RA: +75.736 [2] mas/yr Dec.: +16.724 [2] mas/yr |
| Parallax (π) | 10.3023±0.0957 mas [2] |
| Distance | 317 ± 3 ly (97.1 ± 0.9 pc) |
| Absolute magnitude (MV) | 0.52 [1] |
| Details | |
| Mass | 2.25? [5] M☉ |
| Radius | 3.98+0.11 −0.13 [2] R☉ |
| Luminosity | 44.3±0.5 [2] L☉ |
| Temperature | 7466+217 −105 [2] K |
| Rotational velocity (v sin i) | 110 [4] km/s |
| Age | ~900 [5] Myr |
| Other designations | |
| BD+86°3444, HD 221525, HIP 115746, HR 8938, SAO 3916 [6] | |
| Database references | |
| SIMBAD | data |
HD 221525 is a single [7] star near the north celestial pole [5] in the constellation Cepheus. At an apparent magnitude of 5.56, [1] it can be seen with the naked eye under dark skies. It is about 30 times fainter than the nearby prominent star Polaris. [8] Based upon parallax measurements, HD 221525 is located at a distance of approximately 317 light years from the Sun, [2] but is drifting closer with a radial velocity of −11 km/s. [1]
This object is an A-type star with a stellar classification of A7IV [4] or A8III, [3] suggesting it is an evolving star on the subgiant or giant branch, respectively. It has a relatively high rate of spin, showing a projected rotational velocity of 110 km/s. [4] The star has four [2] times the radius of the Sun and is radiating 44 [2] times the Sun's luminosity from its photosphere at an effective temperature of 7,466 K. [2]
