Cassiopeia (constellation)

Cassiopeia constellation
Latin name	Cassiopeia
Latin genitive	Cassiopeiae
Abbreviation	Cas
Right ascension	22 h 57 m 05 s to  03 h 41 m 14 s
declination	+ 46 ° 40 ′ 33 ″ to  + 77 ° 41 ′ 32 ″
surface	598.407 deg² rank 25
Completely visible	90 ° N to 11.5 ° S
Observation time for Central Europe	all year round
Number of stars brighter than 3 mag	4th
Brightest star (size)	Schedir (2.24)
Meteor streams	December-phi-Cassiopeidae
Neighboring constellations ( clockwise from north )	Cepheus lizard Andromeda Perseus giraffe
swell	IAU ,
From the Uranometria by Johann Bayer .

Kassiopeia , Latin Cassiopeia , is a conspicuous constellation in the northern sky and, for Central Europe, circumpolar , i.e. a region of the sky that is visible all year round.

description

The constellation Cassiopeia as seen with the naked eye

The five main stars of Cassiopeia form a distinctive W or M in the sky, which is why we also speak of heaven-W or heaven-M . The point in the middle of this star formation points in the direction of the north polar star .

In the vicinity of the star β Cassiopeiae ( Caph ), the easternmost star, the Kolur runs with 0 ° right ascension - the “prime meridian” of the sky.

The Cassiopeia region is very rich in stars , as the Milky Way runs through the constellation. Several open star clusters can be observed here.

history

Photo of the constellation Cassiopeia

Cassiopeia and Perseus 2011; HRO

Cassiopeia is one of the 48 constellations of ancient astronomy that were mentioned before Ptolemy .

In the course of time there have been attempts to rename the constellation, for example in the 17th century when it was associated with the biblical Mary Magdalene . However, these efforts did not prevail.

Tycho Brahe observed a supernova in Cassiopeia in 1572 ( SN 1572 ).

In the Cassiopeia is the after sun strongest radio source in the sky, as Cassiopeia A is called. It is the remnant of a supernova that became visible from Earth around 1680. There are no known records of this.

mythology

The Greek mythology after was Cassiopeia , the wife of aithiopischen King Cepheus and mother of Andromeda . The vain Cassiopeia drew the wrath of the gods because she claimed to be even more beautiful than the Nereids , the daughters of the sea god Nereus . The Nereids turned to Poseidon at this insult , who then sent a terrible sea monster to devastate the shores of the land. According to an oracle, the country could only be freed from the curse if Andromeda, the only child of the royal couple, were sacrificed to the monster. Andromeda was eventually chained to a rock and awaited her cruel fate. At the last moment the hero Perseus rushed over and killed the beast. As a reward he received Andromeda as his wife.

All the characters in the story were immortalized in the sky, the sea monster in the form of the constellation whale .

Celestial objects

Stars

B.	F.	Names or other designations	size	Lj	Spectral class
γ	27	Gamma Cassiopeiae	1.6 to 3.4	00550	B0 IVpe
α	18th	Schedir , Shedir, Schedar	2.24	00230	K0 IIIa
β	11	Caph , Cheph, Kaff, Al Saman al Nakah	2.3	00055	F2 IV
δ	37	Ruchbah , Rukbat, Ksora	2.68 to 2.74	00100	A5 III-IVv
ε	45	Segin	3.3	00440	B3 III
η	24	Achird	3.44	00019th	G3 V + K7 V
ζ	17th	Fulu	3.69	00600	B2 IV
	50	50 Cassiopeiae	3.95	00160	A2 V
ρ	7th	Rho Cassiopeiae	4.1 to 6.1	10,000	F8-M5 Ia0pe
κ	15th	Kappa Cassiopeiae	4.17	04000	B1 Iae
θ	33	Marfark , Marfak	4.34	00137	A7 V
ι			4.45	00142	A3p + F5 + K3
ο	22nd		4.48	00900	B5 III + F8
	48		4.54	00117	A3 IV + F2 V
υ 2	28		4.61	00206	G8 IIIb
χ	39		4.68	00204	G9-K0 IIIb
ψ	36		4.72	00193	K0 III + A
λ	14th		4.74	00355	B7 Vn + B8 V
ξ	19th		4.80	01100	B2 V
υ 1	26th		4.83	00407	K2 III
	1		4.84	01100	B0 IV
τ	5		4.87	00173	K1 III
σ	8th		4.88	01500	B1 V + B3 V
ν	25th		4.90	00390	B9 III
π	20th		4.94	00174	A5 V
φ	34		4.95	02800	F0 Ia + B9 + B6 Ib + B3 + B5
	4th		4.96	00770	M1 III
ω	46		4.97	00700	B8 III
		V509 Cassiopeiae	5.1	~ 11,000	G0 Ia0 + B1 V
μ	30th		5.12	00024.6	G5 VIb + M VIsd
	42		5.18	00281	B9 V
	49		5.22	00430	G8 III
	47		5.27	00109	F0 Vn + G1 V
	40		5.28	00450	G8 III
	31		5.31	00318	A0 Vnn
	12		5.38	00760	B9 III
	23		5.42	00800	B8 III
	6th	6 Cassiopeiae	5.43		A3 Iae + A3
	43	V557	5.56	00440	A0sp
	32	RU	5.56	00363	B9 IV
	10		5.57	00980	B9 IIIe
		HR 8832	5.57	0021.35	K3 V
	21st	Y Z	5.63	00290	A2 IV
	2		5.68	02000	A5 III
	44		5.78	00910	B8 IIIn
	38		5.81	00095	F6 V
	9		5.90	02700	A1 III
	13		6.18	00720	B6 V
	35		6.33	00239	A2 Vnn
	16		6.47	00570	B9 III

Schedir (Arabic for “breast”) is the brightest star in Cassiopeia with an apparent magnitude of 2.24 . It is a star of the spectral class K0 about 230 light years away .

Caph (Arabic for "palm") is about 55 light years away and belongs to the spectral class F2.

Ruchbah (Arabic for "knee") is around 100 light years away and belongs to the A5 spectral class.

Rho Cassiopeiae is a yellowish hypergiant . It is one of the largest known stars with 740 times the diameter of our sun .

KPD 0005 + 5106 is a white dwarf and, with a surface temperature of around 200,000 Kelvin, is one of the hottest known stars.

Double stars

object	Sizes	distance
η	3.44 / 7.51	13 "
ι	4.6 / 6.9	2.5 "
φ	5.0 / 7.0	134 "
λ	5.3 / 5.6	0.6 "

Eta Cassiopeiae is a binary star system only 19.4 light years away. The system consists of a yellowish shining star of the spectral class G0 and a reddish companion of the class M0.

The system ι Cas is 150 light years away and consists of two whitish-blue stars of the spectral classes A4 and F5. η and ι Cas are easy to separate in the telescope .

The system φ Cas is at 10,000 light years much further away from the sun. Its stars belong to the spectral classes F0 and B5. Seen from the earth, the two components are far apart at 134 arc seconds and can therefore be resolved into individual stars with prism binoculars .

λ Cas is 300 light years away and consists of two stars of the spectral classes B8 and B9. Seen from the earth, the components are only 0.6 arc seconds apart. To separate them into single stars, you need a larger telescope.

Variable stars

The variable stars V376 Cas and V633 Cas as seen by the Hubble Space Telescope

object	size	period	Type
β	2.27 to 2.31	0.104 days	δ Scuti star
γ	2.47 to 3.40		irregularly variable
δ	2.68 to 2.74	759 days	Coverage variable
ρ	4.1 to 6.1		irregularly variable
6th	5.43		"Shell star"
R.	4.8 to 13.6	431 days	Mira star
SU	5.7 to 6.2	1.9493 days	Cepheid
V 509	5.1		semi-regular

Gamma Cassiopeiae is an irregularly variable star of the spectral class B0 at a distance of 800 light years. At its maximum it achieves a brightness of 1.6 mag and is thus even brighter than Schedir. The star is a powerful X-ray source in the sky. Presumably it is a close binary star system, consisting of a giant star and a neutron star .

SU Cas is a variable star of the Cepheid type . With a regular period of 1.9493 days, its brightness changes from 5.7 to 6.2 mag. It is 800 light years away and belongs to the spectral class F6.

V509 Cassiopeiae is a semi-regular yellow supergiant . With a radius of 910 solar radii, it is one of the largest stars in the Milky Way. V509 Cas is the second brightest star in the stellar association Cep OB1. The two young variable Herbig Ae / Be stars V376 and V633 Cas, which are surrounded by complex reflection nebulae , also met with particular interest .

Messier and NGC objects

Messier (M)	NGC	other	size	Type	Surname
52	7654		6.9	Open star cluster
103	581		10.6	Open star cluster
	281		14th	Emission nebula
	457		8.5	Open star cluster	Owl pile
	559		8th	Open star cluster
	654		7.5	Open star cluster
	663		8th	Open star cluster
	7789		10.5	Open star cluster	Herschel's spiral cluster

Since the Milky Way runs through Cassiopeia, this region is very rich in stars and contains some interesting objects, such as open star clusters . The French astronomer Charles Messier included two of them in his catalog of foggy objects. However, the double star cluster h and Chi Persei visible in the photo belong to the constellation Perseus .

The open star cluster Messier 52 , 5000 light-years away , was discovered by Charles Messier in 1774 while observing a comet that was visible that year . M52 is a very rich star cluster that appears as a foggy spot in binoculars. In the telescope, 80 to 100 stars become visible at higher magnification.

Messier 103 is an open star cluster about 6000 light years away. In the binoculars it appears as a misty spot. It can only be resolved into individual stars in the telescope.

The emission nebula NGC 281 is about 10,000 light years away. The telescope shows that a group of stars is embedded in the nebula. As with the Orion Nebula , the object is a star formation region.

The star cluster NGC 457 , 5000 light years away , was discovered by Wilhelm Herschel in 1787. In the telescope, the sight is reminiscent of an owl with spread wings, with the brightest stars supposed to represent the eyes. The brightest star in the cluster can already be seen with the naked eye.

NGC 559 is approximately 6000 light years away. A faint nebula appears in the binoculars; in the telescope the cluster can be broken down into individual stars.

NGC 654 is 7,000 light years away. In a medium telescope with an aperture of 6 to 10 cm, a compact star cluster with many groups of two and three stars can be seen.

NGC 663 is also 7000 light years away and is a little south of NGC 654. Even in binoculars, the star cluster is a very worthwhile object that shows two star-rich areas. With increasing magnification, more and more stars appear in the telescope, including some easily separable double stars.

The open star cluster NGC 7789 , 6000 light years away , was discovered by Caroline Herschel in 1783 . In the binoculars it appears as a misty cloud. A multitude of stars becomes visible in the telescope. NGC 7789 is one of the richest star clusters in the northern sky.

See also

• List of constellations

Web links

Commons : Cassiopeia constellation  - collection of images, videos and audio files

• List of stars in the constellation Cassiopeia