The night sky of the Northern Hemisphere contains not onlyso long and noticeable objects as Orion or the Great Bear. There are many and much inferior to them in size constellations. Relatively small dimensions, however, do not make such heavenly drawings less interesting. Constellation Dolphin - one of similar objects. It occupies a relatively small area, but several quite curious objects are located on its territory.
Constellation Dolphin for children first appearsduring his acquaintance with ancient Greek mythology. In one of the legends, the god of the oceans Poseidon blazed with passion Nereide Amfetrit. Beauty did not want to become the lover of the sea owner and fled from him. The dolphin helped to restore the nereid. Grateful Poseidon in return gave him a place in the sky. Since then, the constellation Dolphin and decorates the dome over his head.
The unobtrusive Dolphin has bright neighbors.The constellation is located near the asterism Summer Triangle, formed by such famous luminaries as Vega, Deneb and Altair. With the Dolphin, the celestial drawings of the Eagle, Pegasus, Arrow, Lesser Horse, Chanterelle and Aquarius are also bordered. It can be observed on clear nights practically throughout Russia, with the exception of the most northern regions. The ideal time is from June to September. The characteristic form of the constellation (reminiscent of a kite) makes it easily recognizable, of course, provided there are no clouds and other factors that impair visibility.
The constellation of the Dolphin in the sky covers an area of 189square degrees. In its composition there are thirty luminaries, which can be discerned with the naked eye. However, only three of them can be called more or less bright, since they are characterized by the fourth stellar magnitude. They all enter into the main asterism of this heavenly figure, called the Job's Coffin. In total it is four stars. This alpha, beta, gamma and epsilon Dolphin.
The first in brightness
Beta constellation is the most visible pointthis heavenly figure. Its brightness is estimated at 3.63m. The light is called Rotanev and is located in the 97 st. years from the Sun. Beta Dolphin is a multiple system consisting of two components. Both of them belong to the sub-gigants of the spectral class F5. The distance dividing the two stars is very small, so the pair is not distinguishable in every telescope. The luminosity of the brighter component of the system is 18 times greater than the analogous parameter of the Sun. This same characteristic of a less visible star is 8 times more significant than that of our luminary.
Elements of systems rotate with a period of 26.7 years. According to studies, their masses exceed the solar mass by about 2.5 times.
The light described above is somewhat inferior tobrightness of Saulocin. It is an alpha constellation, also a double system. Its main component belongs to the spectral class B9. From the Sun it is separated by a distance of 240 light years. A characteristic feature peculiar to all stars of this type is the rapid rotation. Speed in the equator reaches 160 km / s. This is approximately 70 times greater than that of the Sun. To date, scientists have not determined exactly the type of Saulocin. According to one data, it refers to simple stars of the main sequence. The results of some calculations allow us to define it as a subgiant at the beginning of the evolutionary path.
The second component of the system is distant from the first by 12 astronomical units. They rotate with a period of 17 years. Apparently, the companion of Saulozin in many ways is similar to Sirius.
Origin of names
Contrary to usual, the names of Alpha and beta Dolphinare not Arabic or Greek terms. For the first time the names appeared in the catalog, released in the beginning of the XIX century in the observatory of Palermo. Somewhat later, the British astronomer Thomas William Webb discovered that the names Saulocin and Rotanev, when they were read from right to left, were named Nicolaus Venator. That's the name of astronomer Piazzi's assistant, Cachatore. Which of the two, himself Nicolaus or his boss, has become the author of such names is still a mystery.
Созвездие Дельфин вмещает на своей довольно modest territory not only of the luminary. Nebulae NGC 6891 and NGC 6905 are located here. The first of them has 11 magnitude magnitude, and the second one is 12. Both, like the heavenly pattern itself, are quite small in area.
Кроме того, созвездие Дельфин украшено шаровым accumulation NGC 6934. It is located near the epsilon of this heavenly figure. A fairly large globular cluster is characterized by a magnitude of 8.9 m. The second object similar to it, NGC 7006, is also considered quite bright. From the Earth it is separated approximately 185 thousand light years.
But this is not all - there is one more object,decorating the constellation Dolphin. Photo it is quite easy to find on the Internet. This is the New Delphine 2013. The uniqueness of the object is that shortly before its discovery it was known as a dim 17-magnitude star. When she was discovered by the amateur astronomer Koichi Itagaki, it was much brighter. According to scientists, the star suddenly began to shine 25,000 times stronger. It probably refers to the classic New. Such objects are a double system of a white dwarf and a massive cold luminary. Because of the small distance between them, the substance of the larger star flows to the smaller component, and it warms up. As a result, sooner or later an explosion occurs, in which the stars remain unscathed. Such luminaries can flare up repeatedly.
A small constellation Dolphin, apparently, is under the close supervision of astronomers. Perhaps, it will present many more surprises.