Whale (constellation)
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Constellation whale |
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| Latin name | Cetus |
| Latin genitive | Ceti |
| Abbreviation | Cet |
| Right ascension | 23 h 56 m 25 s to 03 h 23 m 47 s |
| declination | −24 ° 52 ′ 22 ″ to + 10 ° 30 ′ 52 ″ |
| surface | 1231.411 deg² rank 4 |
| Completely visible | 64.8 ° N to 79.8 ° S |
| Observation time for Central Europe | autumn |
| Number of stars brighter than 3 mag | 2 |
| Brightest star (size) | Deneb Kaitos (2.04) |
| Meteor streams | |
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Neighboring constellations ( clockwise from north ) |
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| swell | IAU , |
The whale ( Latin / technical language Cetus ) is a constellation in the vicinity of the celestial equator .
description
The whale is a very extensive but not very conspicuous constellation of the autumn sky between the Pisces and the Eridanus River . The largest part extends below the celestial equator , so that in our latitudes it is not particularly high above the horizon .
The constellation does not have a distinct shape, as most of its stars have a brightness less than 3 m and are therefore not very noticeable.
Inside the whale are the well-known variable stars Mira and Tau Ceti , a yellow dwarf star only 11.9 light years away, which is similar to our sun .
history
In ancient Mesopotamia , a sea monster was seen in the constellation Tiamat , which embodied the original cosmic female principle.
Since the constellation lies below the ecliptic , the sun, moon and planets move over it. For the early Greeks , the stars therefore represented the entrance to the underworld. The constellation was later identified as the sea monster in connection with the legend of Andromeda .
Ptolemy included the constellation in his description of the 48 constellations.
After the Frisian pastor David Fabricius discovered the star o Ceti in the constellation in 1596, Johann Ph. Holwarda recognized in 1639 that the brightness of the star changed significantly over the course of a year. In 1662 he was baptized “ Mira ”, the “miraculous”, by Johann Hevelius . The discovery was of great importance because it refuted the prevailing thesis at the time that the stars were eternal and immutable.
In 1807 the fourth asteroid Vesta was discovered in the whale .
mythology
In Greek mythology , the whale was a sea monster, probably Keto or Ketos , to which the beautiful Andromeda , daughter of King Cepheus and Cassiopeia , was to be sacrificed. Cassiopeia had offended the Nereids , the daughters of the sea god Nereus , by claiming that they were even more beautiful. The Nereids turned to the sea god Poseidon and demanded the punishment of the vain Cassiopeia. Poseidon then sent a sea monster to plague the shores of Cepheus' realm. According to an oracle , the beast could only be appeased by sacrificing Andromeda, the only child of the royal couple. Andromeda was chained to a rock and awaited her fate, but was saved at the last moment by the hero Perseus , who killed the beast. As a reward for this he got Andromeda as his wife.
Cepheus , Kassiopeia , Andromeda and Perseus were also immortalized as constellations in the sky.
Celestial objects
Stars
| B. | F. | Names or other designations | size | Lj | Spectral class |
|---|---|---|---|---|---|
| ο | 68 | Mira | 2.0 m to 10.1 m | 417 | M7 III |
| β | 16 | Deneb Kaitos , Diphda, Rama Secunda | 2.04 m | 96 | K0 III |
| α | 92 | Menkar | 2.54 m | 220 | M1 IIIa |
| η | 31 | Deneb Algenubi | 3.46 m | 118 | K1 III |
| γ | 86 | Kaffaljidhm , Al Kaff al Jidhma | 3.47 m | 82 | A2 + G5 |
| τ | 52 | Tau Ceti | 3.49 m | 11.9 | G8 V |
| ι | 8th | Shemali | 3.56 m | 290 | K1 III |
| ζ | 55 | Baten Kaitos (star) , Bunda | 3.76 m | 260 | K0 III |
| υ | 59 | 3.99 m | 250 | M1 III | |
| δ | 82 | 4.08 m | 800 | B2 IV | |
| μ | 87 | 4.27 m | 100 | F0 IV | |
| π | 89 | 4.3 m | 300 | B7 V | |
| ξ 2 | 73 | 4.30 m | 300 | B9 III | |
| ξ 1 | 65 | 4.36 m | |||
| 7th | 4.44 m | ||||
| 2 | 4.55 m | ||||
| χ | 53 | 4.66 m | 100 | F2 + G1 | |
| σ | 76 | 4.74 m | |||
| ψ 1 | 17th | 4.77 m | |||
| 20th | 4.78 m | ||||
| ε | 83 | 4.83 m | |||
| κ | 96 | 4.84 m | |||
| ν | 78 | 4.87 m | |||
| ρ | 72 | 4.88 m | |||
| 6th | 4.89 m | ||||
| 46 | 4.90 m | ||||
| 56 | 4.92 m | ||||
| 3 | 4.99 m | ||||
| 37 | 5.0 m | 80 | F3 + G7 | ||
| T | 5.0 to 6.9 m | ||||
| 66 | 5.5 m | 70 | F8 + G4 |
The brightest star in Cetus, β Ceti is 96 light years from the sun away. It is an orange giant star belonging to the spectral class K0.
The name Deneb Kaitos is of Arabic origin and means "tail of the whale".
α Ceti is a red giant of the spectral class M1, 220 light years away . The old Arabic name Menkar could be derived from "shoulder", "snout" or "nostrils".
τ Ceti ( Tau Ceti ) is one of the Sun's closest neighbors at a distance of only 11.9 light years .
Double stars
| system | Sizes | distance |
|---|---|---|
| γ | 3.5 m / 7.3 m | 2.8 " |
| κ | 4.7 m / 6.8 m | 184 " |
| 37 | 5.1 m / 7.9 m | 49.7 " |
| 66 | 5.7 m / 7.6 m | 41.0 " |
γ Ceti ( Kaffaljidhm ) is a binary star system 82 light years away, which consists of a whitish glowing main star of the spectral class A2 and a yellowish companion of the class G5. The pair of stars can be resolved into single stars with a medium-sized telescope .
κ Ceti is 100 light years away and consists of two stars of the spectral classes F2 and G1. The two stars are at a wide angular distance of 184 arc seconds from the earth and can be seen as single stars even in prism binoculars .
The system 66 Ceti is 70 light years away and consists of two stars of the spectral classes F8 and G4. Due to the angular distance of 16.5 arc seconds, a small telescope is sufficient for separation.
Variable stars
| object | size | period | Type |
|---|---|---|---|
| ο | 2.0 to 10.1 m | 331.9 days | Pulsation variable |
| T | 5.0 to 6.9 m | 159 days | semi-regularly changeable |
The star Mira (ο Ceti), 417 light years away, changes its brightness periodically over a period of around 332 days. It can become noticeably bright at a maximum of up to 2 m , at a minimum the brightness can drop to 8 to 10 m . It is then invisible to the naked eye.
The star is the namesake of a group of variable stars , the Mira variable . They are pulsation-changing stars that rhythmically inflate and contract again. Mira stars are red giants or supergiants with a relatively cool surface of 3,000 Kelvin . Their luminosity is 100 times higher than that of our sun, as they can have huge diameters of several billion kilometers.
Messier and NGC objects
| Messier (M) | NGC | other | size | Type | Surname |
|---|---|---|---|---|---|
| 77 | 1068 | 8.9 m | Galaxy | ||
| 45 | 10.6 m | Galaxy | |||
| 157 | 10.4 m | Galaxy | |||
| 223 | 13.4 m | Galaxy | |||
| 244 | 12.9 m | Galaxy | |||
| 246 | 8.5 m | Planetary nebula | |||
| 247 | 11 m | Galaxy | |||
| 720 | 10.2 m | Galaxy | |||
| 908 | 10.2 m | Galaxy | |||
| 936 | 10.1 m | Galaxy | |||
| IC 1613 | 9.2 m | Galaxy |
There are several galaxies in the whale, two of which can already be observed with a smaller telescope.
M 77 is a bright Seyfert galaxy of type Sb. At a distance of 50 million light years it is the most distant Messier object.
NGC 246 is a planetary nebula 1,500 light years away . In the telescope it can be seen as a nebulous disk containing two stars of the 12th magnitude . One of the stars is a white dwarf star , the remnant of a star that has shed its outer gas shell.
NGC 247 is an Sd-type spiral galaxy 8 million light years away. It was discovered by Wilhelm Herschel in 1784 . From the earth the galaxy can be seen in edge position. In the telescope it appears as a narrow nebula.
The Cetus dwarf galaxy is a spheroid dwarf galaxy discovered in 1999 by Alan Whiting, George Hau, and Mike Irwin.
