Dolphin (constellation)
See also: Dolphin (homonymy)
The Dauphin is small a Constellation of the northern Hemisphere, near to the celestial equator.
History
The Dolphin was already one of the 48 constellations indexed by Ptolémée. The origin of its name, on the other hand, is not explicit and two legends are attached to it: the first relates to the néréide Amphitrite, with which Poséidon fell in love and which he kidnapped. Being itself flees, she was convinced by a dolphin that the god of the seas was a correct person. In reward, Poséidon placed the dolphin on the vault of heaven. The second tells that the poet Arion of Méthymne, travelling towards Tarente, was threatened to be thrown over edge by the crew which wanted to steal it and its safety had only with one dolphin, attracted by the music which the poet had asked to play before his execution, and which transported it to good port.
This constellation was also known under the name of the Camel at the Astronome S Arab S and of the Whale of Jonas at the Hebrew .
The two most brilliant stars of this constellation bear strange traditional names, Sualocin (α Delphini) and Rotanev (the star β). They have a not very common origin: appearing for the first time on a star catalog published by the observatory of Palermo in 1814, they come in fact from Nicolaus Venator writes with back, the Latin name ized of Niccolo Cacciatore ( Cacciatore and Venator meaning hunter ), the directing assistant of the observatory to the publication of the catalog.
Observation of stars
The Dolphin is a weak constellation, but its form is very characteristic and emerges easily when the visibility is sufficiently good (Mag 4).It is located immediately at the South-east of the Triangle of summer, directly in the East of the eye of eagle of Altaïr, and in the South of the Cygne.
Principal stars
See also: List of stars of the Dolphin
Sualocin (α Delphini)
Sualocin, the star α of the constellation of the Dolphin (which is slightly less less brilliant besides than its neighbor β), does not exceed the Magnitude connect 3,77. It is about a white star rotating quickly (70 times more quickly than the Sun).
Sualocin is a star doubles: his/her companion is distant of 12 ua and the two stars turn one around the other in 17 years.
β Delphini (Rotanev)
The most brilliant star of the constellation of the Dolphin is well the star β Delphini, which bears also the traditional name of Rotanev since 1814 (see above).
β Delphini is a double star, made up of two under-giants of 4,0 and 4,8 magnitude distant from 13 ua on average and orbiting in 26,7 years.
Other stars
γ Delphini is a double star whose components are with most isolated of 600 ua and at least of 40.
α, β, γ and δ Delphini form a Astérisme called the coffin of Job .
Deneb Dulfim (ε Delphini), an Arab name meaning the tail of the Dolphin , is precisely located at the end of the constellation.
R Delphini is a variable star of the type of Mira (constellation of the Baleine), passing from magnitude 7,6 with the magnitude 13,8 in 285,5 days.
Celestial objects
The Dolphin also contains the Nébuleuse planet gear NGC 6891 and the globular Amas S NGC 6934 and NGC 7006.
See too
- List of stars of the Dolphin
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