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Mirfak

Alpha Per

HIP 15863; Alpha Per; 33 Per DoubleStar Per Visible Level 3 Medium telescope (6-8") - Requires steady seeing
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Physical Properties

Magnitude 1.79
Spectral Type F5Ib
Star Color Yellow (B-V 0.48)
Distance 590.0 ly

Position & Identifiers

RA 03h 24m 19.4s
Dec +49° 51' 40.0"
Constellation Per
HR 1017
HIP 15863
Bayer Alpha
Flamsteed 33 Per

Visibility

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Multiple Star System

Separation 164.0″
Companion Mag 12.8
Position Angle 198°
Star Colors A: Yellow
Discoverer BUP 44

Eyepiece View

32x Dawes: 1.9″ TFOV: 1.6°
Realistic = true angular size
N E 198° A (1.8) B (12.8)

Sep: 164.0″ · PA: 198° · N up, E left

Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 3.1″

Size Comparison

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Stellar Lifecycle

Spectral Classification

Hertzsprung-Russell Diagram

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Blackbody Spectrum

Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

Stellar Notes

Mel 20 #605; Per OB3; nebulosity.
MIRPHAK; Mirfak; Marfak; Algenib.

Survey Image

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About Mirfak

Description

Mirfak (Alpha Persei) is the brightest star in the constellation Perseus at magnitude 1.79, located about 510 light-years from Earth. It is a yellow-white supergiant of spectral type F5Ib, about 8.5 times the mass of the Sun and roughly 5,000 times more luminous. Mirfak is the brightest member of the Alpha Persei Moving Cluster (Melotte 20), a nearby open cluster of young blue stars surrounding it.

Observing Tips

Mirfak is easy to find between Cassiopeia and the Pleiades. It lies at the heart of the Alpha Persei Cluster (Melotte 20), which is best appreciated through binoculars — dozens of blue-white stars cascade across a field of about 3 degrees, with the yellow-white Mirfak at the center creating a beautiful color contrast. This cluster is one of the finest binocular objects in the northern sky. The famous Double Cluster (NGC 869/884) lies about 8 degrees to the northeast. Best observed from October through March.

History

The name Mirfak comes from the Arabic 'Mirfaq al-Thurayya' meaning 'elbow of the Pleiades.' Perseus has been recognized as a constellation since ancient times, associated in Greek mythology with the hero who slew Medusa. Mirfak's membership in the Alpha Persei Cluster was established through proper motion studies in the 20th century.

Fun Facts

The Alpha Persei Cluster surrounding Mirfak is about 50-70 million years old and is one of the nearest open clusters to Earth. Despite being in the same cluster, Mirfak's yellow-white color stands out dramatically against its younger, bluer cluster mates. The cluster is slowly dispersing and will cease to exist as a recognizable group within a few hundred million years.