Cassiopeia (constellation)
Cassiopeia constellation |
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---|---|
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 | |
Neighboring constellations ( clockwise from north ) |
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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 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
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 | 550 | B0 IVpe |
α | 18th | Schedir , Shedir, Schedar | 2.24 | 230 | K0 IIIa |
β | 11 | Caph , Cheph, Kaff, Al Saman al Nakah | 2.3 | 55 | F2 IV |
δ | 37 | Ruchbah , Rukbat, Ksora | 2.68 to 2.74 | 100 | A5 III-IVv |
ε | 45 | Segin | 3.3 | 440 | B3 III |
η | 24 | Achird | 3.44 | 19th | G3 V + K7 V |
ζ | 17th | Fulu | 3.69 | 600 | B2 IV |
50 | 50 Cassiopeiae | 3.95 | 160 | A2 V | |
ρ | 7th | Rho Cassiopeiae | 4.1 to 6.1 | 10,000 | F8-M5 Ia0pe |
κ | 15th | Kappa Cassiopeiae | 4.17 | 4000 | B1 Iae |
θ | 33 | Marfark , Marfak | 4.34 | 137 | A7 V |
ι | 4.45 | 142 | A3p + F5 + K3 | ||
ο | 22nd | 4.48 | 900 | B5 III + F8 | |
48 | 4.54 | 117 | A3 IV + F2 V | ||
υ 2 | 28 | 4.61 | 206 | G8 IIIb | |
χ | 39 | 4.68 | 204 | G9-K0 IIIb | |
ψ | 36 | 4.72 | 193 | K0 III + A | |
λ | 14th | 4.74 | 355 | B7 Vn + B8 V | |
ξ | 19th | 4.80 | 1100 | B2 V | |
υ 1 | 26th | 4.83 | 407 | K2 III | |
1 | 4.84 | 1100 | B0 IV | ||
τ | 5 | 4.87 | 173 | K1 III | |
σ | 8th | 4.88 | 1500 | B1 V + B3 V | |
ν | 25th | 4.90 | 390 | B9 III | |
π | 20th | 4.94 | 174 | A5 V | |
φ | 34 | 4.95 | 2800 | F0 Ia + B9 + B6 Ib + B3 + B5 | |
4th | 4.96 | 770 | M1 III | ||
ω | 46 | 4.97 | 700 | B8 III | |
V509 Cassiopeiae | 5.1 | ~ 11,000 | G0 Ia0 + B1 V | ||
μ | 30th | 5.12 | 24.6 | G5 VIb + M VIsd | |
42 | 5.18 | 281 | B9 V | ||
49 | 5.22 | 430 | G8 III | ||
47 | 5.27 | 109 | F0 Vn + G1 V | ||
40 | 5.28 | 450 | G8 III | ||
31 | 5.31 | 318 | A0 Vnn | ||
12 | 5.38 | 760 | B9 III | ||
23 | 5.42 | 800 | B8 III | ||
6th | 6 Cassiopeiae | 5.43 | A3 Iae + A3 | ||
43 | V557 | 5.56 | 440 | A0sp | |
32 | RU | 5.56 | 363 | B9 IV | |
10 | 5.57 | 980 | B9 IIIe | ||
HR 8832 | 5.57 | 21.35 | K3 V | ||
21st | Y Z | 5.63 | 290 | A2 IV | |
2 | 5.68 | 2000 | A5 III | ||
44 | 5.78 | 910 | B8 IIIn | ||
38 | 5.81 | 95 | F6 V | ||
9 | 5.90 | 2700 | A1 III | ||
13 | 6.18 | 720 | B6 V | ||
35 | 6.33 | 239 | A2 Vnn | ||
16 | 6.47 | 570 | 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
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.