The constellation Sagittarius is located between Scorpio and Capricorn. It is interesting in that it has the center of the Galaxy. Also in this large zodiac constellation is the point of winter solstice. Sagittarius includes many stars. Some of them are quite bright. This constellation occupies a large area in the night sky. Many myths and legends are associated with it. At school, constellations are studied as part of the Astronomy course (grade 11). But the curriculum is limited. And lovers of celestial bodies always want to get more knowledge not only about the constellations, but also about the nebulae, and about the galaxies associated with them.
Sagittarius constellation
Sagittarius is undoubtedly one of the most amazing and interesting constellations of the night sky. It is in it that the center of our galaxy is remote for about 30 thousand light-years. It is hidden behind clouds of interstellar dust. Of course, it is impossible to name the stars of the constellation Sagittarius the brightest in the sky, but still some of them reach a visual magnitude of 2.0 and are clearly distinguishable in the sky.
It is believed that in Sagittarius you can observe the most beautiful part of the Milky Way. Here, even with field binoculars, globular clusters and nebulae are visible. The most interesting and, of course, beautiful of them are the Laguna and Omega nebulae (sometimes called Swan), as well as the recently discovered M20. Scientists have proven that in the constellation Sagittarius there is even a black hole, according to astrophysicists, it is located in the center of our Galaxy.
So, it is easy to find the constellation Sagittarius in the sky. Photos taken with powerful telescopes help to find what is not visible to the naked eye. In the northeastern part of the constellation, with a good increase, you can see the dwarf galaxy. It is located not far from the Milky Way. The distance to this misty galaxy of irregular shape is approximately 1.7 million light years. By the way, it was discovered back in 1884 by the scientist E. Barnard.
Naturally, all the objects in the constellation Sagittarius are at different distances from the solar system. To the nearest star - Ros 154 - only 9.69 light years. And this is relatively close by cosmic standards. So, we can say this is our neighbor.
Sagittarius constellation in the sky
This constellation is clearly visible in the night sky in the summer. It appears from the second decade of February, and it can be observed until November. The best conditions for observation are the summer months. Then it disappears. The sun is in Sagittarius from December 18 to January 18. A very interesting fact: it was from the constellation Sagittarius on August 15, 1977 that the world-famous signal "Wow!" Was received - presumably from an alien civilization.
Constellation Myths
The constellation Sagittarius is associated with two centaurs known in mythology: Krotos and Chiron. In almost all atlases of the starry sky at all times, it was conveyed by a drawing that depicted a creature with the torso of a man and the body of a horse. In this form, it was also included in the catalog of Claudius Ptolemy's Almagest.
The most famous Greek myth of the constellation Sagittarius connects him with the wise Chiron, a teacher and mentor of many heroes. It was believed that this particular centaur invented the celestial globe especially for the journey of the Argonauts. On it, he left the site for himself. It is easy to guess that this is the constellation Sagittarius, since it was this centaur that shot perfectly from the bow. But the unexpected happened: the cunning Krotos got ahead of him and took his place. Well, Chiron had to be content with the less honorable constellation of Centaurus.
The constellation Sagittarius was included in the Collection of Svyatoslav in 1073. Slavic tribes it was known under its modern name.
Lagoon nebula
Many cosmic secrets are kept by the constellation Sagittarius. Photos taken with the telescope helped to study in detail the Lagoon nebula, which is located in it. It can rightly be considered a landmark in the summer sky. For those who like to watch the stars, this nebula may seem like a very interesting object. It can be seen even with binoculars.
The Lagoon Nebula is the cradle for the stars. This is a star-forming cluster of cosmic dust. It is oval in shape with a clearly distinguishable center. The nebula contains a star cluster, which turns it into one of the most beautiful objects of the summer night sky. It is 5200 light-years distant from the solar system. Contains globules - dark clouds of stellar material.
Nebula M20
Of course, not only the stars in the constellations are of interest to astronomy lovers. Nebulae are also very interesting. There are several of them in the constellation Sagittarius. But one of the most beautiful, of course, is the M20 nebula. This is the most interesting object for observations on a summer night, however, it can be seen through medium and large aperture telescopes.
The first thing that attracts attention is a few stars in the center of the brightest part of the nebula. Then it becomes noticeable that this object is “torn”. A black hole is visible, dividing the nebula into two parts. This dark area has the shape of the letter "T". At good magnification, it can be seen that the nebula consists of three parts. And next to it is another dimmer object.
Thus, the M20 nebula is represented by three main types of stasis: pink (emission), black (absorbing) and blue (reflecting).
Alpha Sagittarius
The stars of the constellation Sagittarius are not very bright. This is probably why it is not very popular with night sky lovers. What is interesting about this constellation is that alpha is not the brightest star. But still it is visible and has its own name.
Rookbath is a white and blue star. Translated from Arabic, her name means "knee." This is alpha Sagittarius. From the solar system to the star Rukbat, approximately 71.4 parsecs. In the figure, she is on the front left leg at the knee. From here it got its name. In brightness, the Sagittarius alpha is significantly inferior to the star Kaus Australis.
Star Caus Australis
The brightest star in the constellation is Sagittarius ipsilon. The apparent brilliance of Kaus Astralis is 1.79, which corresponds to the brilliance of the stars in the Big Dipper “bucket”. It is clearly visible to the naked eye and is easy to find in the night sky. The mystery of such a bright radiance was discovered by scientists in the middle of the twentieth century. A detailed study of Sagittarius ipsilon revealed that it was a double star.
Kaus Australis is translated as “the southern part of the bow”, which reflects its position in the figure of the constellation. This is the most southern and brightest star in the bow of Sagittarius, consisting of three objects. Apart from Kaus Australis, two more stars form a bow. Astronomy is a precise and creative science, therefore, in addition to official names, objects of the night sky also have personal names. Lambda and Sagittarius beta are called Kaus Borealis and Kaus Meridionalis, respectively. Together with ipsilon they form a “bow”.
Triple Star in Sagittarius
There are different stars in the constellation Sagittarius. Astronomy has data on supergiants and dwarfs. But special attention is always paid to astrophysicists by triple stars. They are very rare and therefore of interest. There is a triple star in the constellation Sagittarius - this is Albaldach. It is approximately 508 light years distant from the solar system. It is entered into star catalogs under the designation "pi Sagittarius".
Albaldach is a very bright star. She is clearly visible with the naked eye, therefore, known since ancient times. The name was given to her by Arab astronomers, who drew attention to her even before our era. From ancient Arabic, the word "Albaldah" is translated as "city". Perhaps they already knew that it was not one, but three stars, which would explain such a name. But confirmation of this fact was not found.
Pi Sagittarius is a three-star system. The main one is a yellow-white giant. Its surface temperature is approximately 6590 Kelvin. It is also interesting that the luminosity of this giant exceeds the solar one thousand times. The star is at the stage of evolution when gravity and its internal pressure lose stability. The yellow-white giant begins to expand and contract. Almost nothing is known about the Albaldah’s satellites. The nature of these stars has not yet been revealed.
Gamma Sagittarius
The constellation Sagittarius includes many more giant stars. However, not all of them are clearly visible to the naked eye. But not Alnasl. This star is located 96 light years from the solar system.
The range of Sagittarius is clearly visible in the sky on moonless nights. Therefore, it has been known to scientists since ancient times. It is also unique in that it has not one, but two Arabic names. The first is Alnasl, which translates as “arrowhead”. The middle name of the star, “Nushbad”, oddly enough, has the same meaning.
In terms of physical characteristics, Alnasl is an orange giant. Its surface temperature is approximately equal to 4760 kelvin. Whether the star has satellites of the planet, like our Sun, has not been established. So far, no signs of their presence have been found.
Sephdar Star - this Sagittarius
This is a double star, it is located at a distance of about 146 light years from the Sun. This Sagittarius has two names: the Arabic "Sefdar" ("frantic warrior") and the Latin "Ira Furoris" ("Flaming Fury"). Until 1928, it was part of the constellation Telescope. Later, when the borders were revised, she was assigned to Sagittarius.