Hunting dogs (constellation)
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Hounds constellation |
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| Latin name | Canes Venatici |
| Latin genitive | Canum venaticorum |
| Abbreviation | CVn |
| Right ascension | 12 h 06 m 22 s to 14 h 07 m 33 s |
| declination | + 27 ° 50 ′ 38 ″ to + 52 ° 21 ′ 35 ″ |
| surface | 465.194 deg² rank 38 |
| Completely visible | 90 ° N to 37.8 ° S |
| Observation time for Central Europe | spring |
| Number of stars brighter than 3 mag | 1 |
| Brightest star (size) | Cor Caroli (2.90) |
| Meteor streams | |
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Neighboring constellations ( clockwise from north ) |
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| swell | IAU , |
The hunting dogs ( Latin / technical language Canes Venatici , abbreviated CVn ) are a small constellation in the northern sky, a little south of the Big Dipper .
description
The hounds are a little conspicuous constellation below the drawbar of the Big Dipper (or below the tail of the Big Bear ). They are formed by three stars, of which only α ( Cor Caroli ) and β Canum Venaticorum are relatively bright. Cor Caroli has an apparent brightness of 2.90 m .
The constellation is often mentioned only because of several galaxies and a globular cluster that were included in the Messier catalog .
history
The hunting dogs were not a separate constellation in antiquity , but were assigned to the Great Bear. On old pictures the stars α and β are represented as the hunting dogs Chara (joy) and Asterion (the star kingdom) of the bear keeper.
As an independent constellation they were first in 1690 through the sky atlas of Johannes Hevelius introduced.
The brightest star, α Canum Venaticorum, bears the name Cor Caroli ( Latin heart of Karl) and is supposed to commemorate the English kings Charles I and Charles II . There are two versions of the origin of the name:
Charles I was executed in 1649. When his son Charles II ascended the throne in 1660 and thus continued the Stuarts dynasty, the star is said to have shone particularly brightly, according to the court physicist Sir Charles Scarborough . The English cartographer Francis Lamb depicted the star as a crowned heart in a star map in 1673 and named it Cor Caroli Regis Martyris.
Court astronomer Edmond Halley , according to another source, paid tribute to Charles II on the occasion of the opening of the Greenwich Observatory , which took place in 1675.
Celestial objects
Stars
| B. | F. | Names or other designations | Vmag | Lj | Spectral class |
|---|---|---|---|---|---|
| α | 12 | Cor Caroli | 2.89 | 110 | A0 + F0 |
| β | 8th | Asterion , Chara | 4.26 | 27 | G0 |
| La Superba , Y | 4.6 to 6.3 | 710 | C7 | ||
| 24 | 4.70 | ||||
| 20th | 4.73 | ||||
| 5 | 4.80 | ||||
| 25th | 4.82 | A7 + F0 | |||
| 6th | 5.02 | ||||
| 21st | BK | 5.15 | |||
| 14th | 5.25 | ||||
| 3 | 5.29 | ||||
| 23 | 5.60 | ||||
| 2 | 5.66 | ||||
| 19th | 5.79 |
Beta Canum Venaticorum , also called Chara, has an apparent magnitude of 4.26 mag. It is only 27 light years away and belongs to the spectral class G0.
Double stars
| object | Vmag | distance |
|---|---|---|
| α | 2.89 / 5.61 | 19.4 " |
| 17th | 5.9 / 6.2 / 6.3 | 79/278 " |
| 25th | 5.0 / 6.9 | 1.8 " |
Cor Caroli can already be recognized as a double star in binoculars . Its companion with a brightness of 5.61 mag is at a distance of 19.4 arc seconds .
The main star α 2 CVn is itself a double star with a companion that orbits it in 5.47 days. Because of the 120 light-years distance, however, the stars have such a small angular distance that they cannot be separated even with large telescopes. Only their spectrum shows periodic changes. Such systems are known as spectroscopic binary stars .
Associated with the revolutions is a change in the magnetic field and the brightness between 2.84 mag and 2.98 mag. α 2 CVn is the namesake of a group of variable stars , the Alpha-2-Canum-Venaticorum-variables , whose characteristic feature is strong magnetic field fluctuations .
The star α 1 CVn is also a spectroscopic binary star.
17 CVn is a triple star 400 light years away. It consists of three stars of the same size with magnitudes 5.9 to 6.3 and the spectral classes F0, B9 and B7. The system can be resolved into single stars with a smaller telescope.
25 CVn is 200 light years away. The two components are 5.0 and 6.9 mag bright and belong to the spectral classes A7 and F0.
Variable stars
| object | Vmag | period | Type |
|---|---|---|---|
| α 2 | 2.84 to 2.98 | 5.47 days | Alpha-2-canum Venaticorum star |
| Y | 5.5 to 6.0 | approx. 157 days | semi-regularly changeable |
Y CVn (also known as La Superba ) is a semi-regularly variable star whose brightness changes between 5.5 mag and 6.0 mag with a period of about 157 days. It belongs to the spectral class C6 and is a reddish star with a high carbon content in the outer shell.
Messier and NGC objects
| Messier (M) | NGC | other | Vmag | Type | Surname |
|---|---|---|---|---|---|
| 3 | 5272 | 6.5 | Globular clusters | ||
| 51 | 5194 | 8.5 | Galaxy | Whirlpool galaxy | |
| 63 | 5055 | 9.0 | Galaxy | ||
| 94 | 4736 | 8.5 | Galaxy | ||
| 106 | 4258 | 8.5 | Galaxy | ||
| 4244 | 10.5 | Galaxy | |||
| 4449 | 9.5 | Galaxy | |||
| 4490 | 10 | Galaxy | |||
| 4631 | 9 | Galaxy | Herring mist | ||
| 4656/57 | 10.1 | Galaxy | |||
| 5195 | 10 | Galaxy |
There are a number of interesting foggy objects in the hunting dogs. The French astronomer and "comet hunter" Charles Messier included a globular star cluster and four galaxies in his catalog of foggy objects ( Messier catalog ) around 1780 .
Messier 3 is a globular cluster about 30,000 light years away that consists of over 100,000 stars. In the binoculars it appears as a round, misty spot. The star cluster is quite compact and can only be resolved into single stars (from 11 mag) in a larger telescope.
Below the first star of the Big Dipper's drawbar you can find Messier 51 , a large spiral galaxy about 30 million light years away, which is also known as the whirlpool galaxy or whirlpool galaxy. The name comes from the fact that in larger telescopes or on long-exposure photographs you can see wonderful spiral structures that are reminiscent of a vortex. However, they cannot be seen in binoculars or a small telescope; the galaxy appears as a foggy patch. At the end of a spiral arm you can find NGC 5195, a smaller companion galaxy (see below).
Messier 63 is a spiral galaxy 30 million light years away. No structures can be seen in the binoculars or medium telescope.
Messier 94 is a spiral galaxy 20 million light years away. In the smaller telescope it appears as a round spot, in the larger one a very bright center is visible.
Messier 106 is a spiral galaxy 30 million light years away. In binoculars and in the smaller telescope it appears as an elongated spot. In the larger telescope, the beginnings of spiral arms and dust clouds can be seen. Incidentally, M 106 was not observed by Charles Messier, but only added to the catalog afterwards.
NGC 4244 is a relatively faint galaxy 20 million light years away.
NGC 4449 is an irregularly shaped, irregular galaxy 16 million light years away. It looks almost rectangular in the telescope. Dust structures become visible in the larger telescope.
NGC 4490 is a spiral galaxy 40 million light years away. In the telescope it appears elongated. The smaller companion galaxy NGC 4485 is 3–4 arc minutes apart . The two galaxies interact and are connected by a bridge of matter; however, this can only be seen on long-exposure photos.
NGC 4631 is an elongated spiral galaxy 25 million light years away, also known as the Herring Nebula because of its shape. Bright structures can be seen in larger telescopes.
NGC 4656/57 is a galaxy 35 million light years away that interacts with NGC 4631. It is quite faint and can only be seen in medium-sized telescopes.
NGC 5195 is the smaller companion galaxy to Messier 51 . Both galaxies are connected by a bridge of matter. NGC 5195 was irregularly deformed by the gravitational effects of the large galaxy. In the telescope it appears as an appendage to M51. If the sky is brightened up in the city, you can only see the galaxy nuclei, but they are almost equally bright.
Some of the above galaxies are among the groups of galaxies Canes Venatici-I group and Canes Venatici-II group , named after this constellation. The groups are adjacent to our local group .
