Big Bear
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Great Bear constellation |
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| Latin name | Ursa Major |
| Latin genitive | Ursae Majoris |
| Abbreviation | UMa |
| Right ascension | 08 h 08 m 31 s to 14 h 29 m 00 s |
| declination | + 28 ° 18 ′ 14 ″ to + 73 ° 08 ′ 18 ″ |
| surface | 1279.660 deg² rank 3 |
| Completely visible | 90 ° N to 14.5 ° S |
| Observation time for Central Europe | Circumpolar constellation. All night all year round. |
| Number of stars brighter than 3 mag | 6th |
| Brightest star (size) | Alioth (1.76) |
| Meteor streams | |
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Neighboring constellations ( clockwise from north ) |
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| swell | IAU , |
.jpg) Engraving from the star atlas by Johann Elert Bode . |
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The Great Bear , called Ursa Major ( Latin for "greater she-bear"), is an extensive constellation in the northern sky . The conspicuous configuration of seven particularly bright stars in this constellation is called the Big Dipper in German-speaking countries . Its two stars Dubhe and Merak - α and β Ursae Maioris - can serve as so-called polar guides to find the North Star . This part of the constellation is circumpolar for Central Europe, i.e. a region of the sky that is visible all year round.
description
Ursa Major is a very extensive constellation, the area of which borders on eight other constellations. The conspicuous Big Dipper star in the Big Bear is an asterism visible all year round in higher northern latitudes . This is formed by seven bright stars of the constellation Great Bear - α, β, γ, δ, ε, ζ, η Ursae Maioris - including its six brightest and Megrez (δ UMa). Three stars form the drawbar of the car - Alkaid (η UMa), Mizar (ζ UMa) and Alioth (ε UMa) - and four more form the box of the car - Megrez, Phekda (γ UMa), Merak (β UMa) and Dubhe (α UMa). With an imaginary line connecting Merak and Dubhe - extending the distance between the two about five times to the north - one can easily find the North Star of the north.
The stars Mizar (ζ UMa) at the bend of the drawbar in the big wagon and Alkor (g UMa), the so-called “little rider”, are well-known eye testers . They have an apparent magnitude of 2.0 mag or 4.0 mag and a separation angle of about 12 arc minutes (0.19 °) and are therefore visually separated as two stars by most people with the naked eye under good visibility conditions . When viewed through a telescope, Mizar turns out to be a double star , consisting of the components Mizar A and B , which in turn can be separated with technical aids. Mizar was already observed with a telescope by Benedetto Castelli in 1617 , photographed by George Phillips Bond in 1857 and spectroscopically examined by Edward Charles Pickering in 1889 . In 2010 it was discovered that Alkor is also a binary star system ( Alkor A and B ).
Polweiser and Polarstern
Two of the stars of the Big Dipper star train in the constellation Great Bear (Ursa Major) are called Pole-wise men . They point to the North Star at the northern celestial pole , which is located on an imaginary connecting line at about five times the distance between the two rear stars of the car body (β UMa = Merak and α UMa = Dubhe ). In addition, other methods are known for finding the pole star. Polaris (α UMi), is the main star of the constellation Little Bear and represents the end of the drawbar in the Little Dipper star train .
mythology
Egypt
- In ancient Egypt the constellation was attested under the names Chepesch and Mesechtiu as the "thigh of Seth ".
Ancient Greece
In classical Greek mythology there are several versions of the origin of the Great Bear:
- In Greek mythology , the three "tiller stars" were originally seen as apples, which gave eternal youth and were guarded by Hesperides , nymphs , who correspond to the little bear .
- The nymph Callisto , impregnated by Zeus , gave birth to a son whom she named Arkas . Zeus' jealous wife Hera then transformed Callisto into a she-bear who had to wander through the woods. Years later, Arkas met his mother while hunting without recognizing her. To prevent the murder of his mother, verstirnte Zeus both to the sky - Callisto as the Great Bear and Arkas as Little Bear . This myth is told by Ovid in his Metamorphoses .
- According to another source, Zeus also transformed Arkas into a bear after the encounter, grabbed the animals by the tails and hurled them into the sky - this gave the constellations the unnaturally long tails. However, Hera was not happy to discover Callisto and her son as the Big and Little Bears in the sky. She called on the sea gods Tethys and Oceanus for help and asked them not to allow the bears to bathe in their waters. So it came about that when viewed from Greece, the two bears orbit the celestial pole forever and never sink deep enough to take a bath.
- The constellation came to heaven as the Big Dipper because the god Dionysus was staying on earth, looking for night quarters, repeatedly turned away and only accepted by a poor shepherd who shared his meager meal with him. In gratitude for the hospitality shown, the god revealed to him the secret of the making of the wine. The shepherd prepared the gift of the gods, filled it in goat tubes and visited him shepherd friends whom he wanted to share in the god potion. After inordinate enjoyment, the shepherds lost their senses: They believed themselves to be poisoned so that the other could steal their flocks from them. But so that he could not enjoy the reward of his outrage, they beat him to death before they die themselves. Sober again they saw what they had done. Dionysus was so sad that the hospitable shepherd had been slain because of his gift that he raised the chariot, on which the goat's tubes with the divine potion had hung, to the sky in honor of the shepherd.
- Aristotle mentioned the constellation in his "Metaphysics", taking the view that not only the seven stars of the chariot, but twelve stars belong to this constellation. Even Homer and later poets like Edmund Spenser , William Shakespeare , Alfred Lord Tennyson and Bertrand Cantat , but Ingeborg Bachmann with the poem Invocation of the Great Bear were inspired by the constellation. The Finnish epic Kalevala mentions it and the painter Vincent van Gogh recorded it in his painting “Starry Night over the Rhone”.
- The name " Arctic " was derived from the Greek word ἄρκτος (árktos) for bear, which means something like "land under the (constellation of) the Great Bear".
Ancient Rome
- The Romans saw in the seven stars of the Big Dipper seven oxen ( Latin septem triones , 'seven oxen'; trio means “threshing ox”), which constantly wander around the celestial pole. From the compound name septemtriones (also: septemptriones ) the more easily pronounced form septentriones arose . In Latin (in Middle High German also as septemtrion and septemtrio ) this word designates the constellation of the bear on the one hand and the north on the other . The singular septentrio , which has been re-formed from this plural form, was also in use , which in addition to the constellation and the north can also denote a north wind. The Latin adjective septentrionalis means "north".
- According to his ancient biographer Suetonius, Emperor Augustus is said to have had numerous birthmarks on his chest and stomach, which could be interpreted as an image of the constellation and as a heavenly sign.
Other cultures
- In the Old Testament , stars are described at Job 9.9 EU and 38.32 EU .
- In the Christian Sky Atlas of Julius Schiller from 1627, this constellation was replaced by the boat of St. Peter.
- For the North American Indians , the box of the wagon represented a bear, the drawbar stars were interpreted as cubs following their mother or as a hunter.
- The Kyrgyz saw seven wolves in the car.
- The Arabs interpreted the box as a coffin, behind which three mourners pulled.
- In China , the car is called the Northern Ladle ( Chinese 北斗七星 , Pinyin běidǒu qīxīng , Japanese. Hokuto shichisei , Kor. Bukduchilseong ). According to ancient Chinese beliefs, the seven stars serve as a sedan chair that the Jade Emperor , who lives at the Pole Star, climbs on for inspection trips to earth. Conversely, Daoist priests can take a spiritual journey to the Heavenly Palace by pacing the star formation. The seven stars are also used as an ornament on Daoist ritual swords.
- In the English-speaking North American region, the car is now often referred to as "the Big Dipper" - the "Big Ladle". In Great Britain and Ireland, however, it is often referred to as "the plow" - the "plow".
- In France , the constellation is interpreted either as the "Large Stielpfanne " (French Grande Casserole ) or the Big Dipper (French Grand Chariot ).
- The big dipper is part of the Starry Plow flag used by the Irish Citizen Army and the flag of the US state of Alaska .
Celestial objects
Stars
| B. | F. | Names or other designations | Apparent brightness likes | Lj | Spectral class |
|---|---|---|---|---|---|
| ε | 77 | Alioth | 1.69 to 1.83 | 81 | A0p |
| α | 50 | Dubhe , Thahr al Dub al Akbar | 1.81 | 124 | K1II-III |
| η | 85 | Alkaid , Benetnasch | 1.86 | 101 | B3 V |
| ζ | 79 | Mizar | 2.23 | 78 | A2 V |
| β | 48 | Merak | 2.34 | 79 | A1 V |
| γ | 64 | Phekda , Phegda, Phekha, Phacd, Phad | 2.41 | 84 | A0 V SB |
| ψ | 52 | Psi Ursae Majoris | 3.00 | 147 | K1 III |
| μ | 34 | Tania Australis , Alkafzah Australis | 3.06 | approx. 230 | M0 III |
| ι | 9 | Talitha (Borealis) , Dnoces, Alphikra Borealis | 3.12 | 48 | A7 IV |
| θ | 25th | Alhaud V , Sarir | 3.2 | 44 | F. |
| δ | 69 | Megrez , kaffa | 3.32 | 81 | A3 V |
| ο | 1 | Muscida | 3.35 | 184 | G4 II-III |
| λ | 33 | Tania Borealis , Alkafzah Borealis | 3.45 | 134 | A2 IV |
| ν | 54 | Alula borealis | 3.49 | about 400 | K3 III |
| κ | 12 | Talitha Australis , Al Kaprah, Alphikra Australis | 3.57 | approx. 360 | A1 Vn |
| H | 23 | 3.65 | 76 | F0 IV | |
| χ | 63 | Alkafzah, Alkaphrah, El Koprah | 3.69 | 196 | K0 III |
| υ | 29 | 3.78 | 115 | F0 IV | |
| ξ | 53 | Alula australis | 3.79 | 29 | |
| G | 80 | Alkor , Saidak | 3.99 | 81 | A5 V |
| f | 15th | 4.46 | 96 | At the | |
| 26th | 4.47 | 267 | A2V | ||
| d | 24 | 4.54 | G4 III-IV | ||
| φ | 4.55 | 437 | A3 IV | ||
| π 2 | 4th | 4 Ursae Majoris | 4.59 | 252 | K2 III |
| 83 | 4.63 | 549 | M2 III | ||
| ω | 45 | 4.66 | 267 | A1 V | |
| τ | 14th | 4.67 | 122 | At the | |
| HR 4132 | 4.72 | 112 | A7 IV | ||
| ρ | 8th | 4.74 | 287 | M3 III | |
| 55 | 4.76 | 183 | A2 V | ||
| σ 2 | 4.80 | 67 | F7 IV-V | ||
| e | 18th | 4.80 | 118 | A5 V | |
| 36 | 4.82 | 42 | F8 V | ||
| 78 | 4.93 | 81 | F2 V | ||
| HR 4072 | 4.94 | 301 | A0sp | ||
| 56 | 4.99 | 492 | G8 II | ||
| 47 | Chalawan | 5.1 | 45.87 | G1 V | |
| 417 | 6.4 | 70 | G0 V | ||
| Sidus Ludoviciana , HD 116798 | 7.6 | A5 |
The brightest star in the constellation Great Bear is Epsilon Ursae Maioris (ε UMa), also called Alioth , about 81 light years away.
Dubhe or Alpha Ursae Majoris (α UMa), the second brightest star in the Big Dipper, is a multiple star system 124 light years away . The main star Dubhe A is a bright orange giant star 30 times the diameter of our sun. He has a companion at a distance of 23 AU that will orbit him in 44 years. Another pair of stars is at a distance of 9,000 AU. The name Dubhe is of Arabic origin and is derived from dahr ad-dubb al-akbar "back of the great bear".
Eta Ursae Majoris (η UMa) is a blue shining star of spectral class B3, 101 light years away . The names Alkaid or Benetnasch are derived from the Arabic al-qāid and al-banāt an-na and roughly mean "the leader" or "daughters who follow the bier". With the daughters (mourning women) the "drawbar stars" are meant, the stretcher or the coffin is the box of the wagon.
The Arabic names Merak and Phekda for the stars Beta (β) and Gamma Ursae Majoris (γ UMa) mean “loin” or “thigh” of the bear. The star Delta Ursa Majoris (δ UMA) bears the name Megrez , Arabic for "root", which means the "base of the tail".
The stars Mizar , Alioth, Megrez, Phekda, and Merak belong to the Ursa Major Group and thus to the Bear Current , an association of around 100 stars that were formed together and move with the same speed and direction within the Milky Way . Our sun is on the edge of the river, but is not one of it. Because of the relative proximity of this stellar stream to the solar system, the appearance of the Big Dipper will change noticeably over the next millennia. The outer two of the seven stars of this constellation, namely Alkaid and Dubhe, are further away, they do not belong to the bear current and have an almost opposite movement of their own .
However, the bear stream also includes stars in other constellations such as Menkalinan in Fuhrmann , Cursa in Eridanus , Gemma in the Northern Crown . It is questionable whether Sirius is part of the Big Dog as previously assumed; Investigations from 2003 and 2005 raised doubts, since the age of the Ursa major group must then be raised to about 500 (± 100) million years. But Sirius is probably only about half his age; that would make him too young to belong to this group.
Observable multiple stars
| system | Apparent brightness likes | distance |
|---|---|---|
| Mizar | 2.3 / 4.0 | 14.4 ″ |
| ξ | 4.3 / 4.8 | 1.7 ″ |
| 78 | 5.1 / 7.4 | 1.5 ″ |
| M 40 | 9.0 / 9.3 | 49 ″ |
Mizar and Alkor appear as double stars to the naked eye . In fact, they are about three light years apart and are not bound to each other by gravity .
After the invention of the telescope and the introduction of spectroscopic investigations, it was found that both stars are multiple stars. Mizar is already visible as a double star in a small telescope. Components A and B are in turn double stars, which can only be detected spectroscopically. It is therefore a four-star system. The Arabic name Mizar means "belt".
Alkor is a binary star system, but its components are too close together to be separated with the telescope. The name is derived from the Arabic al-jawn, "the black horse", which originally meant Mizar.
The double star ξ Ursae Majoris , 27 light years away, can already be observed with a small telescope. The two roughly equally bright stars orbit each other once every 60 years.
Variable stars
| star | m | period | Type |
|---|---|---|---|
| Alioth | 1.75 to 1.78 | 5.088 days | Alpha 2 -Canum Venaticorum Star |
| AE Ursae Majoris | 10.86 to 11.52 | 2.06 hours | SX phoenix star |
| TO Ursae Majoris | 14.5 to 19.3 | 114.84 min | AM Herculis star |
| AR Ursae Majoris | 14.2 to 15.9 (p) | 115.92 min | AM Herculis star |
| VY Ursae Majoris | 5.73 to 6.32 | 120.4 days | Irregularly changeable |
The brightest variable star in the Great Bear is Alioth (ε Ursae Majoris), the right "drawbar star ". It is a white shining star 81 light-years away, three times the diameter and four times the mass of our sun. Its shell is enriched with the elements oxygen , europium and chromium . The star changes its brightness over a period of 5.088 days. The Arabic name Alioth means "fat tail", which means a certain breed of sheep .
VY Ursae Majoris, about 2500 light years away, is one of the reddest stars in the sky. Its brightness changes without any noticeable regularity.
Messier and NGC objects
| Messier (M) | NGC | Surname | m | Type |
|---|---|---|---|---|
| 40 | 9.0 / 9.3 | Double star | ||
| 81 | 3031 | 6.9 | Spiral galaxy | |
| 82 | 3034 | 8.4 | Spiral galaxy | |
| 97 | 3584 | Owl Nebula | 11.0 | Planetary nebula |
| 101 | 5457 | Firewheel Galaxy | 7.9 | Spiral galaxy |
| 108 | 3556 | 10.0 | Spiral galaxy | |
| 109 | 3003 | 9.8 | Spiral galaxy | |
| 2841 | 7.9 | Spiral galaxy | ||
| 3077 | 9.8 | Spiral galaxy |
The Big Dipper contains a number of foggy objects that the French astronomer Charles Messier included in his catalog .
At 40 there is a double star about 500 light-years away. Johannes Hevelius had recorded a foggy object at this position, which, however, is due to the lack of resolution of his huge air telescope . Messier recognized the binary star nature and included the object in his catalog.
The galaxies M 81 , M 82 and NGC 3077 are members of a galaxy cluster 13 million light years away .
The most massive galaxy in the cluster is M 81. It can already be seen as a foggy spot in prism binoculars . The galaxy M 82 is only 1 ° north. At low magnification, the two galaxies can be observed together in the telescope. We see M 82 from the side. Dark clouds of dust can be seen in larger telescopes. The galaxy was clearly visibly deformed by the gravity of M 81.
M 97 is a planetary nebula at a distance of 2500 light years. It is the ejected gas envelope of a star. In binoculars and small telescopes it can be seen as a round spot. In larger telescopes, two dark areas become visible, which gave the nebula the name “Owl Nebula”. It is reminiscent of an owl's head with two dark eyes.
M 108 is a galaxy 45 million light years away that we see from the side. Dark and light structures become visible in the telescope. At low magnification, M 108 and M 97 can be seen together.
The galaxy M 101 is about 27 million light years away. It is very extensive and can be seen as a nebula even with binoculars. Impressive spiral arms are visible in larger telescopes and on long-exposure photographs.
See also
Web links
Individual evidence
- ^ A New View Of Mizar. In: leosondra.cz. Retrieved July 20, 2020 .
- ^ Karl Ernst Georges: Comprehensive Latin-German concise dictionary . 8th edition. WBG, Darmstadt 1913 reprint 1992, 2nd volume, p. 2611.
- ^ Bernhard D. Haage: A new text testimony to the plague poem of Hans Andree. In: Specialized prose research - Crossing borders. Volume 8/9, 2012/2013, pp. 267–282, here: p. 280.
- ↑ The Big Brockhaus . 15th edition. FA Brockhaus, Leipzig 1934, 17th volume, p. 300.
- ↑ Stephen Little (ed.): Taoism and the Arts of China, Chicago 2000, pp. 200 and 216.
- ↑ Jeremy R. King, Adam R. Villarreal, David R. Soderblom, Austin F. Gulliver, Saul J. Adelman: Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group . In: Astronomical Journal . Volume 15, No. 4, 2003, pp. 1980-2017. ( Page no longer available , search in web archives )
- ↑ Wayback Machine. October 5, 2017, accessed July 20, 2020 .
- ↑ a b c VSX