The night sky of the Northern Hemisphere contains not only such extended and noticeable objects as Orion or Ursa Major. There are many constellations significantly inferior to them in size. The relatively small dimensions, however, do not make such celestial drawings less interesting. The constellation Dolphin is one of such objects. It occupies a relatively small area, but several rather interesting objects are located on its territory.
Legend
The constellation Dolphin for children first appears during an acquaintance with ancient Greek mythology. In one of the legends, the god of the oceans Poseidon inflamed with passion Nereid Amfetrite. The beauty did not want to become the lover of the sea master and ran away from him. The dolphin helped return the Nereid. The grateful Poseidon in return granted him a place in heaven. Since then, the constellation Dolphin has also adorned the dome above his head.
Accommodation
The unobtrusive Dolphin has quite bright neighbors. The constellation is located near the asterism Summer Triangle, formed by such famous luminaries as Vega, Deneb and Altair. Dolphin is also bordered by the celestial drawings of Eagle, Pegasus, Arrows, Little Horse, Lysicek and Aquarius. You can watch it on clear nights almost throughout Russia, with the exception of the northernmost regions. The ideal time is from June to September. The characteristic form of the constellation (resembles a kite) makes it easily recognizable, of course, provided there are no clouds and other factors that impair visibility.
Asterism
The constellation Dolphin in the sky covers an area of ââ189 square degrees. It consists of thirty luminaries that can be distinguished with the naked eye. However, only three of them can be called more or less bright, since they are characterized by a fourth magnitude. All of them are included in the main asterism of this heavenly drawing, called the Tomb of Job. In total, it is four stars. These are Alpha, Beta, Gamma and Dolphin epsilon.
First in brightness
The beta constellation is the most prominent point in this celestial pattern. 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 subgiants of the spectral class F5. The distance separating the two stars is very small, so the couple is far from visible in every telescope. The luminosity of the brighter component of the system is 18 times higher than the similar parameter of the Sun. The same characteristic of a less noticeable star is 8 times more significant than that of our star.
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 luminosity described above is somewhat inferior in brightness to Saulocin. This is an alpha constellation, also a binary system. Its main component belongs to spectral class B9. It is separated from the Sun by a distance of 240 light years. A characteristic feature common to all stars of this type is its rapid rotation. The speed in the equator reaches 160 km / s. This is about 70 times larger than that of the Sun. To date, scientists have not determined exactly the type of Saulocin. According to some sources, 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 12 astronomical units distant from the first . They rotate with a period of 17 years. Apparently, the satellite of Saulocin is in many respects similar to Sirius.
Origin of names
Contrary to custom, the Alpha and Beta Dolphin names are not Arabic or Greek terms. The names first appeared in a catalog issued at the beginning of the 19th century at the Palermo Observatory. Somewhat later, the British astronomer Thomas William Webb discovered that the names Saulocin and Rotanev, when read from right to left, give the name Nicolaus Venator. That was the name of the assistant astronomer Piazzi Kachatore. Which of the two, Nicolaus himself or his boss, became the author of such names is still a mystery.
Interesting objects
The constellation Dolphin contains in its rather modest territory not only luminaries. Nebulae NGC 6891 and NGC 6905 are located here. The first of them has 11 magnitude, and the second - 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 celestial pattern. A fairly large globular cluster is characterized by a magnitude of 8.9m. The second similar object, NGC 7006, is also considered quite bright. About 185 thousand light-years separate it from Earth.
But this is not all - there is another object that adorns the constellation Dolphin. A photo of it is quite simple to find on the Internet. This is New Dolphin 2013. The uniqueness of the object is that shortly before its discovery, it was known as a dim star of 17 magnitude. When discovered by amateur astronomer Koichi Itagaki, she was much brighter. According to scientists, the star suddenly began to shine 25 thousand times stronger. She probably belongs to the classic New. Such objects are a binary system of a white dwarf and a massive cold luminary. Due to the small distance between them, the substance of the larger star flows to the smaller component, and it heats up. As a result, sooner or later an explosion occurs in which the stars remain unharmed. Such luminaries can flash repeatedly.
The small constellation Dolphin, as can be seen, is under the close supervision of astronomers. Perhaps it will present many more surprises.