Constellation Dolphin - small but interesting

The night sky of the Northern Hemisphere contains not only such 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 comparatively small area, but several quite curious objects are located on its territory.

Legend

The constellation Dolphin for children first appears during the acquaintance with the ancient Greek mythology. In one of the legends, the god of the oceans, Poseidon, was blazed with the passion of Nereid Amfetrit. Beauty did not want to become a lover of the sea master 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.

Accommodation

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 shape of the constellation (reminiscent of a kite) makes it easily recognizable, of course, provided there are no clouds and other factors that impair visibility.

Asterism

The constellation of the Dolphin in the sky covers an area of 189 square 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 point of this heavenly figure. Its brightness is estimated at 3.63m. The luminary is called Rotanev and is located in 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 separating 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.

Alpha

The light described above is somewhat inferior in brightness to 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 a 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 the alpha and beta of the Dolphin are 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 read from the right to the left give the name Nicolaus Venator. That's the name of astronomer Piazzi's assistant astronomer. Which of the two, himself Nicolaus or his boss, has become the author of such names is still a mystery.

Interesting objects

Constellation Dolphin holds on its rather modest territory not only the luminary. Nebulae NGC 6891 and NGC 6905 are located here. The first of them has 11 magnitude, and the second one is 12. Both, like the heavenly pattern itself, are quite small in area.

In addition, the constellation Dolphin is decorated with a globular cluster 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 another object that decorates the constellation of the 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, she 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.