Mirfak or Alpha Persei (Alp Per) is the brightest naked eye star in the constellation Perseus. With an apparent magnitude of 1.79, Mirfak is the 35th brightest star in the entire sky (see: 50 Brightest Stars ). Its absolute magnitude is -4.5 and its distance is 592 light years. The Equinox J2000 equatorial coordinates are RA = 03h 24m 19.4s, Dec = +49° 51' 40".
Mirfak has a spectral type of F5Ib, a surface temperature of 6600° Kelvin and a luminosity 5400 times the Sun. It has a mass of 11 solar masses and a diameter 56 times the Sun.
The image above shows the uncropped view of Mirfak (North is up) through the Takahashi E-180 Astrograph.
Mirfak is yellow-white supergiant (spectral type F5 Ib) with a luminosity 5,000 times and its diameter 62 times that of our Sun. It has a similar spectrum to Procyon, though the latter star is much less luminous.
In the Hertzsprung-Russell Diagram, Alpha Persei lies very close to the region in which Cepheid variables are found. It is thus useful in the study of these stars, which are extremely important standard candles.
Mirfak is in the middle of a cluster of stars known as the Alpha Persei Cluster, or Melotte 20, which is easily visible in binoculars and includes many of the fainter stars of Perseus. Mirfak is circumpolar when viewed from the latitude of New York (41°).
- Object: Mirfak
- Other Names: Alpha Persei, HR1017, HD20902, HIP15863
- Object Type: bright star
- Object Data: Apparent Magnitude = 1.79, Absolute Magnitude = -4.5, distance = 592 light years
- Object Position (Equinox J2000): RA = 03h 24m 19.4s, Dec = +49° 51' 40", Constellation = Perseus
- Date/Time: 2011 Dec 29 06:48:28 UTC
- Location: Bifrost Astronomical Observatory, Portal, AZ
- Mount: Astro-Physics 1200GTO
- Telescope: Takahashi Epsilon 180 Hyperbolic Astrograph
- Camera: Canon EOS 550D (Rebel T2i) (modified with a Baader UV/IR filter)
- Field of View: 1.70° x 2.56° at 1.7 arc-sec/pixel (web version: 10.0 arc-sec/pixel)
- Exposure: 2 x 240s, f/2.8, ISO 800
- File Name: Mirfak-01w.jpg
- Processing (Adobe Camera Raw): Graduated Filter, Vignetting Correction, Noise Reduction, White Balance, Curves
- Processing (Photoshop CS5): Average Images, Curves, Noise Reduction
- Original Image Size: 3454 × 5179 pixels (17.9 MP); 11.5" x 17.3" @ 300 dpi
- Rights: Copyright 2011 by Fred Espenak. All Rights Reserved. See: Image Licensing.