9 Persei
Blue supergiant star in the constellation Perseus
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9 Persei is a single[11] variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; 9 Persei is the Flamsteed designation. This body is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of about 5.2. It is moving closer to the Sun with a heliocentric radial velocity of −15.2 km/s.[5] The star is a member of the Perseus OB1 association of co-moving stars.[12]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 02h 22m 21.43482s[1] |
| Declination | +55° 50′ 44.3518″[1] |
| Apparent magnitude (V) | 5.15 - 5.25[2] |
| Characteristics | |
| Spectral type | A2 Ia[3] |
| U−B color index | −0.11[4] |
| B−V color index | +0.37[4] |
| Variable type | α Cyg[2] |
| Astrometry | |
| Radial velocity (Rv) | −15.20[5] km/s |
| Proper motion (μ) | RA: +0.374[1] mas/yr Dec.: −1.798[1] mas/yr |
| Parallax (π) | 0.7603±0.1139 mas[1] |
| Distance | approx. 4,300 ly (approx. 1,300 pc) |
| Absolute magnitude (MV) | −4.73[6] |
| Details | |
| Mass | 10.5[7] M☉ |
| Radius | 88.9+3.8 −2.8[1] R☉ |
| Luminosity | 12,331±2,189[1] L☉ |
| Surface gravity (log g) | 1.74[8] cgs |
| Temperature | 9,840[9] K |
| Metallicity [Fe/H] | +0.26[8] dex |
| Rotational velocity (v sin i) | 25[3] km/s |
| Other designations | |
| i Persei, 9 Per, V474 Per, BD+55°598, FK5 2159, GC 2836, HD 14489, HIP 11060, HR 685, SAO 23256, CCDM J02224+5551A, WDS J02224+5551A[10] | |
| Database references | |
| SIMBAD | data |
This is a blue supergiant with a stellar classification of A2 Ia,[3] a massive star that has used up its core hydrogen and is now fusing heavier elements. It is an Alpha Cygni variable (designated V474 Persei), a type of non-radial pulsating variable. It ranges in magnitude from 5.15 down to 5.25.[14] The star has 10.5[7] times the mass of the Sun and has expanded to 89[1] times the Sun's radius. It is radiating over 12,000[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 9,840 K.[9]
9 Persei has one visual companion, designated component B, at an angular separation of 12.3″ and magnitude 12.0.[15]