The first thing that attracts us in the night sky is, of course, the constellations. Photos and their names seem to be more consistent with each other than real celestial drawings and their designations, since the image, as a rule, is provided with auxiliary lines and is devoid of objects that "interfere" with the perception of the image. However, the beauty of the constellations can only be understood by looking for them overhead.
For the convenience of determining the position of the stars, the earthly sky is divided by the equator into the northern and southern hemispheres. Directly on this dividing line are the equatorial constellations. Their list includes, among other things, the celestial image of the Eagle, the mythical servant of Zeus.
Location
The constellation, located near the celestial equator, is available for observation almost anywhere in the world. The best time to look for it in the northern hemisphere is from July to August. The constellation Eagle includes about a hundred luminaries visible from Earth with the naked eye. Some of them are located on the eastern branch of the Milky Way.
The brightest star of the Eagle constellation - Altair - is included in the asterism Summer Triangle. His other twothe peaks are Deneb, related to the celestial image of Cygnus, and Vega, alpha Lyra, the second brightest star in the northern hemisphere. This neighborhood makes it easier to search in the sky for both Altair itself and the entire Eagle.
Myth
Legends and myths about constellations always tell why this or that pattern caught fire in the sky, and also interpret the meaning of its name. The eagle is a majestic bird, but strength, pride and wingspan are not enough to shine over the heads of the living after death.
According to the legends, the Eagle, illuminating the night sky, once served Zeus, the formidable god of the ancient Greeks. He was honored with the great honor of wearing thunderbolts and giving them when needed. Zeus trusted his Eagle with important assignments. From time to time, he delivered the person he needed to the god, as in the myth of Ganymede. Often the Eagle was the weapon of Zeus, his punishment for the guilty. The legend of Prometheus, perhaps, is ahead of all other legends and myths about the constellations in popularity. The eagle was the same bird that every day tormented the titan who gave fire to people. The suffering of Prometheus continued until Hercules, who killed the bird, saved him. For faithful service, the saddened Zeus placed the Eagle in the sky.
Alpha
The most prominent star in the constellation Aquila is Altair. By the name, you can judge which celestial drawing it belongs to. Altair means "flying eagle" in Arabic. In terms of brightness among all the stars, it takes the twelfth place. Alpha Eagle owes this not only to its size and brilliance, but also to the relatively small distance that separates it from the Sun. According to scientists, it is 16.8 light years. Of all the objects of spectral class A, only Sirius is closer to us.
Altair is a white main sequence star, slightly less than twice as massive as the Sun. At the same time, its luminosity is 11 times greater than the corresponding parameter of the central space object of our system. As observations have shown, the brightness of Altair changes slightly, by hundredths of a stellar magnitude. Today, in connection with this, it is referred to as variables of the Scutum delta type.
Not quite a ball
A feature of Altair is its shape. It is far from being a perfect sphere: the diameter of the Eagle's alpha in the equatorial region is somewhat larger than in the plane of the poles. This inequality is created due to the high speed with which Altair rotates around its axis. At the equator, it reaches 286 km/s. One such rotation takes less than 9 hours. Under the action of centrifugal forces, the star was deformed. As a result, its poles are closer to the core than the equatorial line, and heat up more because of this.
Eagle Family
Altair together with beta and gamma of this constellation are almost on the same straight line. They and several other less noticeable luminaries are referred to as the Eagle Family asterism. The three bright points of the constellation are also united under a different name - the Libra Rocker. True, to the zodiac celestial pattern, patronizing people bornin September, this asterism is irrelevant. Thanks to him, the constellation Eagle is easy enough to find.
Triple system
Beta Eagle, Alshain (translated from Arabic as "hunting falcon"), is 44.7 light years away from the Sun and is a system of three stars. The first component is an orange subgiant of magnitude 3.17. Now this star is in the process of becoming a red giant. In terms of mass, it exceeds our luminary by 1.3 times.
Beta Eagle B is Alshain's companion, a red dwarf with an apparent magnitude of 11.4. It is significantly inferior to the first component in size: its mass is 0.3 of the corresponding parameter of the Sun. The third star, Beta Eagle C, has an apparent brightness of +10.5.
Orange Giant
Another star in the constellation Eagle, belonging to the asterism Rocker of Libra, is Tarazet (gamma). It ranks second in brightness among all the luminaries of this celestial pattern. At the same time, the distance from the Sun to the Orel gamma significantly exceeds this indicator for Altair and Alshain. It is estimated at 460 light years. If not for this value, then Tarazet would have outstripped Alpha Orel, since its brightness is more than 2.5 thousand times higher than the solar one. The apparent magnitude of the object is 2.72.
The size of the star is quite impressive: the diameter of Tarazet is so huge that if you place the luminary in the place of the Sun, it will occupy all the space up to the orbit of Venus.
Gamma Eagle is not a single star. Tarazet has a companion with a visible brilliance of 10, 7.
Variables
The constellation Eagle has several delta Cephei variables, also called Cepheids. Among them is this Eagle, which changes its brightness in the range from 3.5 to 4.4m with a period of just over 7 days. It was discovered by E. Pigott a year before Goodrayk's well-known discovery of the variability of the Cepheus delta. Three more variable stars of this celestial pattern are available for observation from Earth with binoculars: FF, TT and U Eagle.
In partnership with a black hole
One of the most interesting objects in the constellation Eagle is SS433, located at a distance of 18 thousand light years from the Sun. The star is an eclipsing X-ray binary system. Presumably, one of its components is a black hole, the second is a star of spectral type A. Both revolve around the same center of mass in about thirteen days.
This system appeared as a result of the explosion of a massive star, which happened about ten thousand years ago and caused the formation of the W50 nebula. A black hole is the remains of a collapsed core of a supernova.
The matter of the star of the system flows constantly towards the black hole, forming an accretion disk around it and heating up. As a result of the increase in temperature, x-rays are emitted from the surface of the object all the time. Jets of matter are ejected into space in different directions. They rush into space at a speed of about a quarter of the speed of light. In general, the picture of the interaction of objects in the system is similar to those illustrations that are often accompanied in various manuals by an explanation of the processes occurring next toblack hole.
New
In 1999, the constellation Aquila shone a little differently than usual. One of the luminaries increased its brilliance by 70 thousand times. Subsequently, it was named V1494. The brightness of the star increased from 1 to 4 December. It belongs to the so-called classical novae, which are a system of two companions, one of which is a white dwarf. The matter from the second star flows to the dwarf and accumulates, sooner or later leading to an explosion. The latter is seen from the Earth as a gradually increasing brilliance. According to existing data, after such a cataclysm, the system does not break up. The substance in it continues to flow from companion to companion. Centuries later, another explosion is to be expected.
Planetary systems
Several stars belonging to the celestial image of the Eagle have planets. These include, for example, xi Eagle. This is an orange giant, surpassing the Sun in a number of parameters: its dimensions are 12 times larger, and its luminosity is 69 times larger. The mass is also more significant than the sun, but not on such a scale - only 2.2 times. The surface temperature of Xi Eagle, on the other hand, is lower, not even reaching 5,000 degrees.
A planet orbiting a star was discovered in 2008 by Japanese astronomers. It belongs to the class of gas giants, surpassing Jupiter in mass by 2.8 times. It takes the planet 136 days to make one revolution around Xi Eagle.
Nebula
Eagle is a constellation (the photo is shown below), which has a very beautiful object on its "territory". This is a nebulaThe shining eye or NGC 6751. The hot star at the center of the cosmic formation resembles a pupil. The radiation and winds created by it form streams on telescope images, much like the iridescence of colors.
The Shining Eye is a classic planetary nebula with a diameter about 600 times the size of the solar system. The exact value of the parameter is estimated at 0.8 light years. The nebula is separated from our star by 6.5 thousand light years.
The Starry Image of the Eagle is another patch of sky full of spectacular objects. The drawing of the constellation, photos and names of individual luminaries hide a lot of interesting information. Thanks to the capabilities of modern equipment, everyone can see what this or that part of the celestial Eagle looks like, remote from us for many tens and hundreds of light years.
The uniqueness of the information age in which we live lies in the fact that you can very quickly find all the facts related to a particular object: legends (about the names of constellations or their origin) belonging to different peoples and centuries, the latest data on features of stars, finally, photographs of telescopes. Today, raising your eyes to the night sky, you can not only enjoy what you see, but very clearly imagine how amazing beauty is hidden in its depths.
