Alpha Persei
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 03h 24m 19.37009s |
| Declination | +49° 51′ 40.2455″ |
| Apparent magnitude (V) | 1.82 |
| Characteristics | |
| Spectral type | F5 Ib |
| U−B color index | +0.38 |
| B−V color index | +0.483 |
| Astrometry | |
| Radial velocity (Rv) | −2.04 km/s |
| Proper motion (μ) | RA: +23.75 mas/yr Dec.: −26.23 mas/yr |
| Parallax (π) | 6.44±0.17 mas |
| Distance | 510 ± 10 ly (155 ± 4 pc) |
| Absolute magnitude (MV) | −5.1 |
| Details | |
| Mass | 7.3±0.3 M☉ |
| Radius | 53.1±1.4 R☉ |
| Luminosity | 4,018±53 L☉ |
| Surface gravity (log g) | 1.9±0.04 cgs |
| Temperature | 6,439±80 K |
| Metallicity [Fe/H] | −0.159±0.016 dex |
| Rotational velocity (v sin i) | 19.0±0.2 km/s |
| Age | 41 Myr |
| Other designations | |
| Mirfak, Mirphak, Marfak, Algeneb, Algenib, α Persei, α Per, Alpha Per, 33 Persei, BD+49 917, CCDM J03243+4951A, FK5 120, GC 4041, HD 20902, HIP 15863, HR 1017, IDS 03171+4930 A, PPM 46127, SAO 38787, WDS J03243+4952A | |
| Database references | |
| SIMBAD | data |
Alpha Persei (Latinized from α Persei, abbreviated Alpha Per, α Per), formally named Mirfak (pronounced /ˈmɜːrfæk/ or /ˈmɪərfæk/), is the brightest star in the northern constellation of Perseus, outshining the constellation's best-known star, Algol (β Persei). Alpha Persei has an apparent visual magnitude of 1.8, and is a circumpolar star when viewed from mid-northern latitudes.
Alpha Persei lies in the midst of a cluster of stars named as the eponymous Alpha Persei Cluster, or Melotte 20, which is easily visible in binoculars and includes many of the fainter stars in the constellation. Determined distance using the trigonometric parallax, places the star 510 light-years (160 parsecs) away.