Mu Cassiopeiae is a binary star

Binary star

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...

 system in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Cassiopeia

Cassiopeia (constellation)

Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today...

. This system shares the name Marfak with Theta Cassiopeiae

Theta Cassiopeiae

Theta Cassiopeiae is a star in the constellation Cassiopeia. It has the traditional name Marfark or Marfak, which it shares with μ Cassiopeiae, and the name was from Al Marfik or Al Mirfaq , meaning "the elbow".In Chinese, , meaning Flying Corridor, refers to an asterism consisting of θ...

, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow".

In 1961 the close binary nature of this system was discovered by Nicholas E. Wagman at the Allegheny Observatory

Allegheny Observatory

The Allegheny Observatory is an American astronomical research institution, a part of the Department of Physics and Astronomy at the University of Pittsburgh. The facility is listed on the National Register of Historical Places The Allegheny Observatory is an American astronomical research...

. Since then the orbital elements of the two stars have been fairly well established. The two stars are separated by a semimajor axis of 7.61 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

s with distance range of 3.3-11.9 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

s. In 1966, the individual components were first resolved by the American astronomer Peter A. Wehinger using the 84-inch reflector at the Kitt Peak National Observatory

Kitt Peak National Observatory

The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson...

, allowing an initial estimate of separate masses.

Compared to other nearby stars, this pair are moving at a relatively high velocity of 167 km/s through the Milky Way

Milky Way

The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

 galaxy

Galaxy

A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...

. They are low metal, Population II stars that are thought to have formed before the galactic disk first appeared.

This star will be in constellation Perseus

Perseus (constellation)

Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...

around 5200 AD.

External links

• SolStation entry
• Mu Cassiopeiae by Professor Jim Kaler.