Mu Cassiopeiae
Mu Cassiopeiae, Latinized from μ Cassiopeiae, is a binary star system in the constellation Cassiopeia. This system shares the name Marfak with Theta Cassiopeiae, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". It is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.16. The system is located at a distance of 24.6 light years from the Sun based on parallax, and is moving closer with a high radial velocity of −98 km/s. This star will move into the constellation Perseus around 5200 AD.

Mu Cassiopeiae is given as a standard star for the spectral class G5Vb, although it is frequently described as a subdwarf, meaning it has a luminosity below that expected for a G5 main sequence star. The metallicity, or abundance of heavy elements, is about one-sixth that in the Sun. It is slightly smaller than the Sun with less mass and a lower luminosity.

This is one of the first high-velocity stars to be identified. Compared to other nearby stars including the Sun, this pair are moving at a relatively high velocity of 167 km/s through the Milky Way galaxy. They are low metal, Population II stars that are thought to have formed before the galactic disk first appeared.
Q50053
binary star
Concept
Q8928
constellation
Concept
Q10464
Cassiopeia
CEL
Q1569726
Theta Cassiopeiae
CEL
Q124313
apparent visual magnitude
Concept
Q531
light year
Concept
Q525
Sun
CEL
Q906561
parallax
Concept
Q240105
radial velocity
Concept
Q10511
Perseus
CEL
Q25377588
spectral class
Concept
Q6220
subdwarf
Concept
Q3450
main sequence
Concept
Q217030
metallicity
Concept
Q321
Milky Way
Concept
Q318
galaxy
Concept
Q1436016
Population II
Concept
Q682966
Mu Cassiopeiae
CEL
Q682966
Mu Cassiopeiae
CEL
5200-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
5200
DATE
+5.16^^http://www.w3.org/2001/XMLSchema#decimal
5.16
NUMBER
+24.6^^http://www.w3.org/2001/XMLSchema#decimal
24.6
NUMBER
+98^^http://www.w3.org/2001/XMLSchema#decimal
98
NUMBER
+5^^http://www.w3.org/2001/XMLSchema#decimal
5
NUMBER
+5^^http://www.w3.org/2001/XMLSchema#decimal
5
NUMBER
instance of
constellation
instance of
model item