Cepheus (constellation)
No
- Little Dipper
- Dragon
- Swan
- Lizard
- Cassiopeia
- Giraffe
The Cepheus (Latin Cepheus ) is a constellation of the northern sky.
Description
The Cepheus is not as striking as the constellations Cassiopeia and dragon. Its brightest stars are reminiscent of a house with a pointed roof. From Central Europe Cepheus is visible throughout the year (ie circumpolar ).
Because of precession, the celestial north pole is located in about 3000 years in the constellation Cepheus.
Mythology
Cepheus was the Greek mythology, the king of Ethiopia, husband of Cassiopeia and father of Andromeda. His wife drew the wrath of the gods, as they claimed to be more beautiful than the Nereids, the daughters of the sea god Nereus. The so maligned Nereids turned to the sea god Poseidon and demanded the punishment of the vain Cassiopeia. Poseidon sent a sea monster then from that struck the coasts of Cepheus ' kingdom. The monster could only be appeased by Andromeda was sacrificed to it. Andromeda was expecting her grisly fate chained to a rock, but was saved at the last moment by the hero Perseus, who they got to pay for his wife.
Cepheus, Cassiopeia, Andromeda, Perseus and the monster Keto were immortalized as constellations in the sky. The latter in the shape of the constellation whale ( Cetus ).
Celestial objects
Stars
α Cephei, the brightest star in Cepheus, is about 49 light years away. He is a whitish- yellowish shining star that has approximately the size of our sun.
The name Alderamin is of Arabic origin and means " the right arm ".
Double stars
The star β Cephei is a double star in 230 light years away. The system can be dissolved for a smaller telescope in single stars.
The Arabic name Alfirk means "the flock".
δ Cephei is a 890 light-years distant binary star. Due to the large angular spacing of 41 arc seconds, the two components are already visible in a bright prism binoculars.
β Cephei and δ Cephei are also variable stars.
Variable Stars
β Cephei is the namesake of a group of variable stars, the Beta Cephei stars. It is pulsationsveränderliche stars with short-term fluctuations in brightness 2-14 hours. β Cephei is about 230 light years away.
δ Cephei is also named after a major group of variables, the Delta Cepheids. These are giant stars with high luminosity, which undergo an unstable stage. They puffed up at regular intervals and contract again. This pulsation can be detected as a regular change in brightness. The luminosity and the Pulsationsdauer are directly related. The more luminous the star, the slower it pulsates. Delta Cepheids can thus be used to determine the distance of star clusters and galaxies.
The star μ Cephei was called by the astronomer William Herschel because of its deep red color Garnet Star. It is a red supergiant with 60,000 times the luminosity of our Sun. Its diameter is estimated to be 1,450 times the sun diameter.
This huge value is exceeded by the supergiant VV Cephei A. Transported into our solar system, the star would reach to the orbit of the planet Saturn. The apparent brightness of the binary system VV Cephei decreases by about 20 percent when the luminous weaker companion is behind the main star.
The hitherto most massive star found is the orange giant hyper RW Cephei. The semiregular star, however, is no longer identifiable with an apparent magnitude of 6.65 m with the naked eye.
Messier and NGC objects
IC 1396 is a star cluster in 2000 light years away. The cluster is embedded in an extended emission nebula, the only on long-exposure photographs is however visible.
NGC 6946 is a spiral galaxy of type Sc in 15 million light -years away.