23.11.202327.05.2017

The constellation Cassiopeia is located in the northern hemisphere of the celestial sphere. It includes about 150 stars that are visible to the naked eye. There are 5 brightest luminaries. In the sky they are located in the form of the Latin letter W. They are easy to distinguish among the shining stellar splendor.

This cluster of luminaries has been known to people since ancient times. In the 2nd century, Claudius Ptolemy included it in his tome "Almagest" along with 47 other constellations. The ancient Greeks associated Cassiopeia herself with the Ethiopian queen, the wife of Kepheus (Cepheus). She was Andromeda's mother. After death, she found herself on the celestial sphere next to her husband, daughter and her beloved Perseus. All these star clusters are nearby. So family ties have been preserved forever, and people have been admiring their relatives ascended into space for thousands of years.

The constellation in question is located opposite Ursa Major, and between them in the sky the Polar Star Ursa Minor is visible. The brightest star is Shedar or Alpha Cassiopeiae. It is located at a distance of 70 parsecs or 228 light years from Earth. It is an orange giant. It rotates slowly around its own axis and makes a full revolution in 102 days. At one time, Shedar was classified as a variable star, but since the 19th century no changes in brightness have been detected.

The rightmost of the 5 bright luminaries is the star Kaf, which means “palm” in Arabic.. It is a subgiant with a yellow-white hue. It is 3 times larger than the Sun and 28 times brighter. The star is currently in the process of cooling and expanding to evolve into a red giant. This star is a Delta Scuti type variable. She belongs to the Main Sequence at the last stage of her life. Kaf is a double star. It has a light satellite about which very little information is available.

The star Navi is in the middle of the top five. The luminary is bright, but does not have a traditional Arabic name. But the ancient Chinese designated it with a word that means “whip.” This is a variable star. At maximum intensity, it eclipses all other stars in the constellation. The cosmic body rotates very quickly and has equatorial swellings. It belongs to the subgiant stars and gradually turns into a giant star. Its mass is 19 times that of the Sun. It emits energy that is equal to 55 thousand suns and shines with a blue-white light. Strong X-ray emission is observed.

Closer to the left edge is the star Rukbach or Delta Cassiopeia. It is a double star system orbiting around the same center of mass. They make a full revolution in 759 days. The distance from them to Earth is 30 parsecs. The main member of the system is a giant star, the radius of which is 4 times that of the Sun. There is an excess of infrared radiation.

The leftmost star is Seguin. Its glow is blue and white. The distance to Earth is 430 light years or 130 parsecs. It is considered one of the brightest stars in the constellation Cassiopeia. The luminary is 6 times the radius of the Sun. There is an interesting suggestion that the Seguin star is kinematically related to the Alpha Persei cluster. Apparently it was once separated from the cluster as a result of tidal interactions.

Constellation Cassiopeia in the night sky

The supernova SN 1572 or Tycho Brahe is of interest. In 1572, astronomer Tycho Brahe noticed the appearance of a new bright star very close to Seguin. She shone in the sky for a year and a half, and then disappeared from the sky. Today we know that it was a supernova explosion. Currently, this formation exists as an object in the radio frequency spectrum and is located at a distance of 7500 light years from Earth, and its dimensions are 20 light years.

This yellow dwarf is very similar to the Sun, Cassiopeia A, which is part of a binary star system. It is called Akhird and is located 19 light years from Earth. The second object is an orange dwarf. Its mass and radius are equal to half that of the sun. The object is cold and dim. Both bodies revolve around the same center of mass, and complete a revolution in 480 years.

The constellation Cassiopeia is also rich in star clusters. This is first and foremost M52. It is an open cluster, in which there are 193 space objects. From Earth it is located at a distance of 5 to 7 thousand light years. In the night sky it is located very close to Cepheus and has a glow that can be seen with binoculars.

Other visible clusters are NGS 457 And NGS 663. They include many stars. The first cluster is located at a distance of 8 thousand light years from Earth and contains 150 stars. And the second is located at a distance of 8200 light years from the blue planet and has about 400 stars.

To find the constellation in question in the sky, you need to draw a straight line through the outermost stars of the Ursa Major bucket and the North Star. It will run into the desired cluster of stars, leaving the constellation Cepheus to the side. Cassiopeia seems to be swinging on a swing with the Big Dipper. When one of them descends to the horizon, the second rises to the zenith, and vice versa. This is explained by the fact that on the celestial sphere they are on opposite sides of the North Star.

Cassiopeia (lat. Cassiopeia) is a constellation in the Northern Hemisphere of the sky.

The brightest stars of Cassiopeia (from 2.2 to 3.4 magnitudes) form a figure similar to the letters “M” or “W”.
The constellation covers an area of 598.4 square degrees in the sky and contains about 150 stars visible to the naked eye; 90 of them are brighter than 6m.
Most of the constellation lies in the Milky Way band and contains many open star clusters.

The constellation Cassiopeia is almost entirely immersed in the so-called summer Milky Way, which already suggests that this constellation can be very rich in deep space objects.

That’s right, there are more than two dozen remarkable open star clusters in Cassiopeia, so the main tool for us today will be powerful astronomical binoculars, or a high-aperture refractor with an aperture of at least 100 mm and a wide field of view. The constellation Cassiopeia is non-setting throughout almost the entire territory of Russia. Only in the very south of the country does a small part of it briefly disappear behind the horizon.

The myth of the constellation Cassiopeia

Cassiopeia was the wife of King Cepheus of Ethiopia (located next to her in the form of a constellation). She once boasted that she was superior in beauty to the Nerids (50 sea nymphs created by the titan Nereus). They got angry and asked Poseidon to punish her. He could not refuse, since he was married to one of them (Amphitrite). He sent Cetus, a sea monster depicted in the constellation Cetus, who was supposed to destroy the kingdom. The king asked the oracle for help and he advised him to give Poseidon his daughter Andromeda. With great difficulty they agreed and chained her to a rock. But at the last moment she was saved by Perseus, whom she later married. However, this is not the end. One of her admirers, Phineus, showed up at the wedding and accused her of treason, since only he had the right to marry her. A battle took place in which Perseus used the head of Medusa the Gorgon. But, since many people looked at her, the king and queen also turned to stone. Poseidon sent Cassiopeia and Cepheus to heaven. But he still punished her, since for half a year the constellation remains turned upside down. Most often she is depicted sitting on a throne and combing her hair.

How to find the constellation Cassiopeia?

The constellation Cassiopeia is usually found by the asterism Tron. It is best for someone to show this Throne - it is enough to see this configuration of stars in the sky once, and it will become recognizable forever!

The constellation Cassiopeia can be found independently as follows:

If you live approximately at the latitude of Moscow, then literally from the very beginning of autumn, when you go outside at about midnight local time, you will find the Tron asterism right above your head, at the zenith. All you have to do is correctly determine the angular dimensions of the throne and mentally build its pattern according to the stars.

The largest angular distance in the Tron asterism, between Seguin and Kaf, is about 13°. The angular distance between the thumb and index finger of an adult’s outstretched hand is 16-18°, so the Throne against the background of an outstretched hand will look approximately as shown in Fig. 5.

Estimation of the angular size of the Throne asterism in the constellation Cassiopeia using an outstretched arm. This image seems to emphasize the compact arrangement of the bright stars of Cassiopeia

An all-season way to determine the location of Cassiopeia is to “target” the beam through already known stars. The best “shot” will be obtained if you continue the line from Aliot (ε UMa) beyond the North Star (α UMa) and you will get an exact hit in Gamma Cassiopeia Navi, and if you look closely you will find that the Big Dipper and the Throne of Cassiopeia asterism are located centrally symmetrically relative to the North Star.

You need to mentally draw a line through Alioth Ursa Major and the North Star - it will lead to the brightest star Cassiopeia Navi. There are other options: from any of the stars of the handle of the Big Dipper, also draw lines to Polaris, all of them will lead to Cassiopeia. In such a position as in Figure 7, Ursa Major and Ursa Minor, Cassiopeia and the Throne can be seen on a late spring evening.

If you look at the Sun from Alpha Centauri, one of the stars closest to us, it will appear in Cassiopeia and will be visible as a 0.5 magnitude star.
Stephen King's novel The Green Mile makes reference to the constellation Cassiopeia: the novel's hero, John Coffey, calls the constellation "Cassie the Lady in the Rocking Chair", which reflects an American folklore reflection of the ancient myth. The constellation Cassiopeia is also mentioned in the novel “The Langoliers”.
The constellation Cassiopeia is also mentioned in the film “Intuition” (2001), where the main character Jonathan (John Cusack) tells the myth about the constellation to a girl named Sarah (Kate Beckinsale).
The star Alpha Cassiopeia is the goal of the expedition in the Soviet science fiction film-duology “Moscow - Cassiopeia / Youths in the Universe”, released by the film studio. Gorky in 1973–1974.
Cassiopeia is the name of the official fan club of the DBSK group
Cassiopeia, in the world of Middle-earth created by the writer J. R. R. Tolkien, corresponds to the constellation Wilvarin (Butterfly).
Flammarion in his book “The Starry Sky and Its Wonders” talks about the work of a certain English writer “The Star ψ Cassiopeia, an amazing history of one of the worlds in space, a description of the peculiar nature, habits, travels and literary works of the local inhabitants.” According to the author, the manuscript of the book was discovered in an empty fireball found in the Himalayas.

W-asterism

Cassiopeia includes an asterism that forms a memorable image of the constellation - W-asterism. It consists of the brightest stars of the constellation, ε (Segin), δ (Rukbah), γ (Navi), α (Shedar) and β (Kaf), forming a figure reminiscent of the Latin letter “W”.

Shedar(Alpha Cassiopeiae) is an orange giant of spectral type K0IIIa at 228 light years. This is a suspicious variable star. The apparent value may vary depending on which photometric system is used. The range contains from 2.20 to 2.23 magnitudes. Located in the lower right corner of the W-asterism. The name Shedar is taken from the Arabic “şadr” - “chest”. It marks the star position - in the heart of Cassiopeia.

Kaf(Beta Cassiopeia) is a subgiant or giant of spectral type F2 III-IV. It is 54.5 light years away from us. This is a Delta Scuti type variable star. Only brighter in this class Altair(star in constellation Aquila and 12th in the sky). This yellow-white star is 28 times brighter than the Sun and 4 times larger. It is currently in the process of cooling and will one day become a red giant.

Delta Scuti variables exhibit brightness variations due to radial and non-radial pulsations at the surface. These are usually giants or main sequence stars of spectral types ranging from A0 to F5.

The average apparent magnitude is 2.27. From the Arabic kaf translates as “palm” (that is, the palm of the Pleiades - a famous cluster in the constellation Taurus). Other traditional names are al-Sanam al-Naqa and al-Qaff al-Khadib.

Together with the stars Alpheraz (Andromeda) and Algenib (Pegasus), Kaf was perceived as one of the Three Guides - three bright stars creating an imaginary line from Kaf to Alferaz to the celestial equator (the point where the Sun passes at the spring and autumn equinoxes).

Navi(Gamma Cassiopeia) is an eruptive variable star that serves as the prototype of the variable stars Gamma Cassiopeia. Exhibits irregular changes in brightness from magnitude 2.20 to magnitude 3.40. It is the central W-shaped star and the brightest in the constellation (now). It is a blue star (spectral type B0.5 IVe), located 610 light years away with 40,000 times the Sun's brightness and about 15 solar masses. Due to rapid rotation, it expands at the equator and creates a “maternity” disk of lost mass and material. The Chinese call it Qih - “whip”. She also has the nickname "Navi", which comes from astronaut Virgil Grissom. Navi is Ivan (in English Ivan is the middle name of an astronaut), written in reverse order. The astronauts used the star as a guide.

Ruckbach(Delta Cassiopeia) is a double star with a period of 460 days. Belongs to spectral class A5. It is 99 light years distant and has an apparent magnitude between 2.68 and 2.74. It ranks fourth in brightness in the cluster. The name comes from the Arabic word for “knee”. Sometimes she is called Xora.

Seguin(Epsilon Cassiopeiae) is a bright blue-white B-class giant 440 light years away. 2500 times brighter than the Sun with an apparent magnitude of 3.34. Age – 65 million years. The star is at the end of a hydrogen fusion cycle. It is distinguished by very weak spectral absorption of helium.

Akhird(Eta Cassiopeiae) is a yellow-white G-type hydrogen dwarf star, slightly cooler than the Sun. The surface temperature is 5730 Kelvin, and the apparent magnitude is 3.45. It is the closest star in Cassiopeia to our system (only 19.4 light years away).

Akhird has a companion, an orange K-class dwarf with an apparent magnitude of 7.51, 11 arcseconds distant. Both are classified as the variable star RS Canes Venatici. They form a close binary star and have active chromospheres that create large star spots. This results in changes in luminosity - the brightness fluctuates by 0.05 magnitude.

Zeta Cassiopeia– blue-white subgiant (B2IV) 600 light years away. Apparent visual magnitude – 3.67. It is an SPB (slow pulsating B) variable star with a magnetic field. The rotation speed is 56 km/s, and the period is 5.37 days.

Rho Cassiopeia– yellow hypergiant (a rare type, since there are only 7 of them in the Milky Way). It belongs to the spectral class G2Ia0e and is located 11,650 light years away. One of the brightest stars. Despite the distance, it can be viewed without technical equipment. 550,000 times brighter than the Sun with an absolute magnitude of 7.5. The apparent visual magnitude ranges from 4.1 to 6.2. It is a semi-regular variable with huge spikes every 50 years (causing the brightness to change). In 2000-2001, the star ejected about 10,000 Earth masses in a single outburst. Scientists believe it exploded as a supernova because it used up most of its nuclear fuel. But if this is so, then the light from the explosion has not yet reached us.

V509 Cassiopeia– G-type supergiant at 7800 light years. The yellow-white star is a semi-regular variable. Luminosity varies within 4.75-5.5.

Notable objects

Star of Tycho Brahe. In 1572, Danish astronomer Tycho Brahe noticed the sudden appearance of a bright new star in the constellation Cassiopeia, near κ Cas. The nova gradually weakened and was no longer visible after sixteen months. Today we know that it was a supernova - one of the last stellar explosions observed in the Milky Way galaxy. Located about 7,500 light-years away, the supernova remnant is nearly 20 light-years in diameter.
Cassiopeia A. This constellation contains one of the most powerful sources of galactic radio emission - Cassiopeia A (Cas A). The flux of radio waves from this region of the sky is many times more powerful than the radio emission from Tycho Brahe's star. In 1951, photographic plates sensitive to red light captured fragments of a small radio nebula associated with Cassiopeia A. Based on the rate of expansion of the nebula, it was calculated that the explosion that gave birth to it probably occurred in 1667. In the sky, this object is located between β Cassiopeia and δ Cepheus.

Other interesting objects in the constellation include:

Open star clusters M52 (NGC 7654), M103 (NGC 581), NGC 457 and NGC 7789,
Dwarf elliptical galaxies NGC 147 and NGC 185 are satellites of the Andromeda Nebula,
Diffuse nebula NGC 281
A giant sphere of gas is the Bubble Nebula (NGC 7635).
Nebulae IC 1805, IC 1848 and IC 1795, which are associated with radio sources W4, W5 and W3, respectively.

> Cassiopeia

An object	Designation	Meaning of the name	Object type	Magnitude
1	M52	No		5.00
2	M103	No	open star cluster	7.40
3	Shedar (Alpha Cassiopeiae)	"Breast"	Orange giant	2.24
4	Kaph (Beta Cassiopeia)	"Palm"	White-blue giant	2.28
5	Navi (Gamma Cassiopeia)	"Ivan is the opposite"	Blue subdwarf	2.47
6	Rukbach (Delta Cassiopeia)	"Knee"	Double star	2.68
7	Seguin (Epsilon Cassiopeia)	Origin unknown	White-blue giant	3.37
8	Achird (Eta Cassiopeia)	Origin unknown	Yellow-white dwarf	3.44
9	Zeta Cassiopeia	No	Blue-white subgiant	3.66
10	Kappa Cassiopeia	No	Blue-white supergiant	4.16
11	Theta Cassiopeia	"Knee"	Blue subgiant	4.34
12	Chi Cassiopeia	No	Yellow giant	4.68
13	Upsilon-2 Cassiopeia	"Front of Clothes"	Yellow giant	4.83

What does the diagram look like? constellation Cassiopeia northern hemisphere: how to find, description with photos, facts, star map, myth and legend, bright stars and objects.

Cassiopeia - constellation, which is in the northern sky. The name was given in honor of the vain and boastful queen in the myths of Ancient Greece.

The constellation Cassiopeia was first recorded in the second century by Ptolemy with other constellations of the Perseus group (except Lizard). It is easy to recognize in the sky because it is shaped like a “W”. It contains several notable objects: open clusters and , the supernova remnant of Cassiopeia A, the star-forming cloud NGC 281 and the NGC 7789 (White Rose) cluster.

Facts, position and map of the constellation Cassiopeia

With an area of 598 square degrees, the constellation Cassiopeia is the 25th largest constellation. Located in the first quadrant of the northern hemisphere (NQ1). It can be found in latitudes: from +90° to -20°. Adjacent to , and .

Cassiopeia
Lat. Name	Cassiopeia (genus Cassiopeiae)
Reduction	Cas
Symbol	Queen on the throne
Right ascension	from 22 h 52 m to 3 h 25 m
Declension	from +46° to +77°
Square	598 sq. degrees (25th place)
Brightest stars (value< 3 m )	Shedar (α Cas) - 2.24 m Cafe (β Cas) - 2.27 m Navi (γ Cas) - variable, 2.47 m Rukba (δ Cas) - 2.68 m
Meteor showers	No
Neighboring constellations	Giraffe Cepheus Lizard Andromeda Perseus
The constellation is visible at latitudes from +90° to -13°. The best time for observation is September-November.

It contains three stars with planets and two Messier objects: M103 (NGC 581) and M52 (NGC 7654). The brightest star is Shedar. The Perseid meteor shower is associated with the constellation. Cassiopeia is part of the Perseus group along with, and. Consider the diagram of the constellation Cassiopeia on a star chart.

The myth of the constellation Cassiopeia

The king asked the oracle for help and he advised him to give Poseidon his daughter Andromeda. With great difficulty they agreed and chained her to a rock. But at the last moment she was saved by Perseus, whom she later married. However, this is not the end. One of her admirers, Phineus, showed up at the wedding and accused her of treason, since only he had the right to marry her. A battle took place in which Perseus used the head of Medusa the Gorgon. But, since many people looked at her, the king and queen also turned to stone.

Poseidon sent Cassiopeia and Cepheus to heaven. But he still punished her, since for half a year the constellation remains turned upside down. Most often she is depicted sitting on a throne and combing her hair.

The main stars of the constellation Cassiopeia

Cassiopeia is distinguished by its unique "W" shape - an asterism created by five bright stars. From left to right: Epsilon, Delta, Gamma, Alpha and Beta Cassiopeia. Explore the bright stars of the Cassiopeia constellation with detailed descriptions and characteristics.

Kaf(Beta Cassiopeia) is a subgiant or giant of spectral type F2 III-IV. It is 54.5 light years away from us. This is a Delta Scuti type variable star. It is brighter than it in this class only (star in and 12th in the sky). This yellow-white star is 28 times brighter than the Sun and 4 times larger. It is currently in the process of cooling and will one day become a red giant.

Delta Scuti variables exhibit brightness variations due to radial and non-radial pulsations at the surface. These are usually giants or main sequence stars of spectral types ranging from A0 to F5.

It is a blue star (spectral type B0.5 IVe), located 610 light years away with 40,000 times the Sun's brightness and about 15 solar masses. Due to rapid rotation, it expands at the equator and creates a “maternity” disk of lost mass and material.

It is a known source of X-ray radiation. The amount is 10 times higher than that of other B or Be class stars. It is a spectroscopic double star. The solar-mass satellite has a magnitude of 11 and a distance of two arcseconds. Rotates every 204 days.

The Chinese call it Qih - “whip”. She also has the nickname "Navi", which comes from astronaut Virgil Grissom. Navi is Ivan (in English Ivan is the middle name of an astronaut), written in reverse order. The astronauts used the star as a guide.

Ruckbach(Delta Cassiopeia) is an eclipsing double star with a period of 460 days. Belongs to spectral class A5. It is 99 light years distant and has an apparent magnitude between 2.68 and 2.74. It ranks fourth in brightness in the cluster. The name comes from the Arabic word for “knee”. Sometimes she is called Xora.

550,000 times brighter than the Sun with an absolute magnitude of -7.5. The apparent visual magnitude ranges from 4.1 to 6.2. It is a semi-regular variable with huge spikes every 50 years (causing the brightness to change). In 2000-2001, the star ejected about 10,000 Earth masses in a single outburst.

Scientists believe it exploded as a supernova because it used up most of its nuclear fuel. But if this is so, then the light from the explosion has not yet reached us.

V509 Cassiopeia– G-type supergiant at 7800 light years. The yellow-white star is a semi-regular variable. Luminosity varies within 4.75-5.5.

Celestial objects of the constellation Cassiopeia

(NGC 7654) is an open cluster 5000 light years away. Its apparent magnitude is 5.0, making it visible through binoculars.

It is 35 million years old and 13 arc minutes (19 light years) in diameter.

The cluster was discovered by Charles Messier in 1774. Among the brightest stars, two yellow giants stand out with magnitudes 7.77 and 8.22.

(NGC 581) is an open cluster 10,000 light years away. Holds 172 stars. Age – 25 million years.

The cluster was discovered by French astronomer Pierre Mechain in 1781. It is noteworthy that this turned out to be the last object that Charles Messier added to his catalogue.

- supernova remnant. It is the most powerful radio source in the sky outside the solar system and was one of the first radio sources discovered in 1947.

This is a cloud of material ejected by an explosion. It is 10 light years in diameter and is expanding at a speed of 4000-6000 km/s. The temperature is 50 million degrees Fahrenheit.

The explosion occurred approximately 11,000 years from Earth. The first supernova light arrived to us only 300 years ago.

(Pacman Nebula) is a large gas cloud in which star formation has recently occurred. Contains a huge amount of ionized atomic hydrogen (H II). Illuminates young, hot, blue stars with ultraviolet light.

It's called the Pac-Man Nebula because it looks like a character from a popular video game.

It is 9500 light years away from Earth. In 1883, it was discovered by the American astronomer E. E. Barnard.

NGC 7789(White Rose) is an open star cluster 7,600 light years away. Apparent magnitude – 6.7. In 1783, it was discovered by British astronomer Caroline Herschel.

The cluster is also called the White Rose or Carolina Rose because the star loops resemble rose petals.

NGC 185(Caldwell 18) is a dwarf spheroidal galaxy 2.08 million light years away. This is a satellite of the Andromeda Nebula. It belongs to the Seyfert type with an active galactic nucleus. Hosts young star clusters and shows evidence of star formation.

It was found by John Herschel in 1787. The first photograph appeared thanks to James Keeler in 1898-1900. He used the Crossley Telescope (36 inches/910 mm), a reflecting telescope located at Lick Observatory (California).

NGC 147(Caldwell 17) is a dwarf spheroidal galaxy 2.53 million light years from Earth. It is also a satellite of the Andromeda Nebula and is part of the Local Group of galaxies. Originally found in 1829 by John Herschel. Apparent visual magnitude – 10.5.

) form a figure similar to the letters “M” or “W”. The constellation occupies an area of 598.4 square degrees in the sky and contains about 90 stars brighter than 6 m (that is, visible to the naked eye). Most of the constellation lies in the Milky Way band and contains many open star clusters.

Cassiopeia

Lat. Name	Cassiopeia (in genus: Cassiopeiae)
Reduction	Cas
Symbol	Queen on the throne
Right ascension	from 22 h 52 m to 3 h 25 m
Declension	from +46° to +77°
Square	598 sq. degrees (25th place)
Brightest stars (value< 3 m)	Shedar (α Cas) - 2.24 m Cafe (β Cas) - 2.27 m Navi (γ Cas) - variable, 2.47 m Rukba (δ Cas) - 2.68 m
Meteor showers	No
Neighboring constellations
The constellation is visible at latitudes from +90° to −13°.
Media files on Wikimedia Commons

Mountains of creation in the star forming region W5 (IC 1848) in Cassiopeia

The constellation Cassiopeia is non-setting throughout almost the entire territory of Russia and in most of it culminates in the zenith region. Only in the very south of the country does Cassiopeia remain entirely in the northern sky all the time, and a small part of the constellation briefly hides behind the horizon.

W-asterism

Stars

Notable objects

Star of Tycho Brahe. In 1572, Danish astronomer Tycho Brahe noticed the sudden appearance of a bright new star in the constellation Cassiopeia, near κ Cas. The nova gradually weakened and was no longer visible after sixteen months. Today we know that it was a supernova - one of the last stellar explosions observed in the Milky Way galaxy. Located about 7,500 light-years away, the supernova remnant is nearly 20 light-years in diameter.

Cassiopeia A. This constellation contains one of the most powerful sources of galactic radio emission - Cassiopeia A(Cas A). The flux of radio waves from this region of the sky is many times more powerful than the radio emission from Tycho Brahe's star. In the city, fragments of a small radio nebula associated with Cassiopeia-A were recorded on photographic plates sensitive to red light. Based on the rate of expansion of the nebula, it was calculated that the explosion that gave birth to it probably occurred in 1667. On the sky, this object is located between β Cassiopeia and δ Cepheus.

Other interesting objects in the constellation include:

open star clusters M52 (NGC 7654), M103 (NGC 581), NGC 457 and NGC 7789,
dwarf elliptical galaxies NGC 147 and NGC 185 - satellites of the Andromeda Nebula,
diffuse nebula NGC 281
giant gas sphere - the Bubble Nebula (NGC 7635).
nebulae IC 1805, IC 1848 and IC 1795, with which W4, W5 and W3 are associated, respectively.

Constellation Cassiopeia (Cas)

Prepared by: website
10-10-2013

Perhaps the circumpolar constellation second in its recognition after the “bucket” of Ursa Major is Cassiopeia, the stars of which form a figure similar to the Latin letter "W". But if we take into account the fourth magnitude star κ Cassiopeia, the figure of the constellation also becomes like... a small ladle!

The constellation is named after Cassiopeia - in Greek mythology, the wife of the Ethiopian king Kepheus (Cepheus) and the mother of Andromeda. According to one version of the myth, Cassiopeia, for her boasting, was tied to a chair, sitting on which she was doomed to circle around the North Pole of the celestial sphere, turning upside down.

The constellation Cassiopeia is one of the 48 constellations mentioned by Ptolemy in his catalog of the starry sky, and is therefore one of the oldest constellations in the starry sky. The main asterism of Cassiopeia is formed by 5 stars of the 2nd and 3rd magnitude, forming a “W”-shaped figure of the constellation. Due to their brightness, they are clearly visible in the sky even in urban light conditions.

In the sky, the constellation Cassiopeia borders on constellations such as Cepheus, Giraffe, Lizard, Andromeda, Perseus and is accessible for observation in the latitude range from +90° N. to -20° S On the territory of Russia there is non-setting constellation.

A simple way to find Cassiopeia in the sky

Before we move on to describing the attractions of this constellation, we will help novice astronomy lovers find it in the sky. To do this, we will first find the “bucket” of the Big Dipper, then the North Star. Now let’s draw a mental straight line from the star Alioth (ε Ursa Major) through the Polar Star further to the same angular segment (see figure above). Here we can easily find the characteristic “W”-shaped figure of the constellation Cassiopeia.

Cassiopeia on a modern star map

Let's get to know the main stars of this constellation. Let's start with the star β Cassiopeia, which is called Kaph. The name of the star, apparently, comes from the letter of the Arabic alphabet “Kaf”, since its outline is very similar to the figure of this constellation. Kaf is a yellow giant of spectral class F. The star's magnitude is +2.28 stars. led However, it is not constant and varies from +2.25 to +2.31 stars. led with a period of 2.5 hours. Before us is a variable star of the δ Scuti type.

Now let's move on to the star α Cassiopeia, called Shedar. Being 230 light years away from Earth, this star, an orange giant, is visible as a star of +2.23 stars. Vel., while the luminosity of Shedar is 500 times greater than the luminosity of our Sun!

At one time, the star Shedar was also considered variable, but since the 19th century there have been no signs of its variability.

Those with small telescopes will be interested in looking at the star η Cassiopeiae, a beautiful double star located 19.4 light-years away. Primary yellow star +3.34 mag. led almost the same spectral class as our Sun, so observing it even with the naked eye, you can imagine what our Sun looks like from a distance of 19 light years. Next to the main yellow star at an angular distance of 13" the second component of this binary system is noticeable - a cooler orange star +7.51 mag.

Next, we will get acquainted with the star γ Cassiopeia, which is called Navi (Navi, from English navigation - navigation). This name was given to the star by American astronaut Gus Grissom, because γ Cassiopeiae has been a navigation star in a number of space missions. And, thanks to its physical characteristics, this star is of undoubted interest. So, in 1937 its brightness was equal to +2.2 mag. However, by 1940 it had weakened to +3.4 magnitude. led In 1949, γ Cassiopeia increased in brightness to +2.9 stars. vel., and by 1965 it became even brighter (+2.7 mag. mag.). Today the brightness of this star is +2.15 stars. led and it is the brightest star in the constellation. The reason for the instability of the brightness is the very rapid rotation of this star around its axis, as a result of which it is strongly flattened at the poles. Given the star's high luminosity, γ Cassiopeiae loses stellar matter accumulating in its equatorial zone, which forms a disk around it, which apparently influences changes in the apparent brightness of the star.

Let us also add that γ Cassiopeia is a spectral double star with a period of rotation of the components around the common center of gravity equal to 204 days. The estimated mass of the satellite roughly corresponds to our Sun.

Now let's turn our attention to the next star of the "zigzag" of Cassiopeia - Rukba (δ Cassiopeia), which in Arabic means "knee". Rukba is an eclipsing variable star with a period of 759 days. The visible brightness of the star varies within insignificant and imperceptible limits for the human eye - from +2.68 to +2.74 stars. led Rukba is 99 light years away from Earth.

The last star of the "W"-shaped constellation is the star ε. It also has a name - Seguin. The star Seguin is 441 light years away from us and in our sky its brightness is +3.38 stars. led Before us is a blue-white giant with a luminosity that is 720 times greater than the luminosity of the Sun!

Now that we have become acquainted with the main stars of the constellation, let's move on to other objects that attract the attention of astronomy lovers. First of all, I would like to draw attention to another variable star in this constellation, designated by the Greek letter ρ. On dark nights, it can easily be found with the naked eye south of the star Kaph (β Cassiopeia) as a star of approximately +4.5 stars. led What is interesting about this star? Despite its ordinary brilliance in the earth's sky, in front of us is a real yellow hypergiant, it is distant from us at a distance estimated at 11,700 - 15,300 light years. ρ Cassiopeia exceeds the Sun in radius by 400 - 500 times, and in luminosity by about 500,000 times!

Animation of the processes occurring with ρ Cassiopeia

P Cassiopeia belongs to the so-called semi-regular variable stars and its brightness varies between +4.4 and +5.1 stars. Vel., but in 1946 it weakened to +6 stars Vel. The interval between individual brightness maxima is about 100 days, but no clear periodicity of fluctuations in the star’s brightness has been recorded. Near the maximum, Cassiopeia's ρ spectrum corresponds to class F8, while it appears to be a reddish star, which is not typical for this spectral class. Sometimes (during brightness fluctuations) the spectral class of a star changes from F8 to K5, and in the mentioned 1946 it even became M5, which corresponds to red stars (by the way, ρ Cassiopeia seems to many observers to be a red star). In any case, this star should be taken under observation and its brightness determined from night to night, since unexpected changes are always possible, including a weakening to 6 stars. led And such observations, undoubtedly, can also have scientific value.

Search map of ρ Cassiopeia and comparison stars

Now information for those who are armed with binoculars or a telescope and are ready to take a walk through the brightest star clusters of the constellation. Let's start with the open star cluster M52 (NGC 7654), located west of the star β Cassiopeia. To search for this object, let’s arm ourselves with binoculars and draw a mental straight line from the star α Cassiopeia through the star β Cassiopeia further to approximately the same angular distance. Here, against the backdrop of scattered stars of the Milky Way, this small open star cluster is located, consisting of two yellowish stars +7.77 and +8.22 stars. Vel., as well as stars of the 11th magnitude. In binoculars, M52 will appear more like a small, hazy speck, but with telescopes with an objective lens of at least 100mm in diameter, individual faint stars in this open star cluster can be seen in a "V" shape.

Another open star cluster in the constellation Cassiopeia visible through binoculars is M103, located near the star δ Cassiopeia. M103 is easy to find with binoculars and is visible as a compact, glowing, hazy speck. It is worth noting that it is better to get acquainted with M103 using binoculars, since due to the small number of stars included in the cluster, when observed through a telescope, it “dissolves” against the background of the surrounding stellar scatterings. But the telescope will help you see the faint stars of this cluster, which is 8,000 light years away from us.

There are other open star clusters in the constellation Cassiopeia, such as NGC 659, NGC 663, NGC 654, as well as NGC 457, which is more than 9,000 light years away and includes about a hundred stars. The star φ Cassiopeiae is visible against the background of this cluster, but it has nothing to do with NGC 457.

In urban light conditions, in which observing deep space objects becomes difficult, we can recommend observing the Queen’s Kite asterism, which is clearly visible through binoculars. The asterism is located slightly east of the star δ Cassiopeia, and the brightest star of this asterism is the star χ Cassiopeia (magnitude +4.7 mag.). The brilliance of the remaining stars included in the asterism is 6–7 stars. size. And in its shape, the asterism is similar to a paper kite. And the larger the diameter of the lens of your optical instrument and the darker the sky, the more scatterings of stars you can see in this corner of the starry sky.

Search map of the Queen’s Kite asterism

Of course, the story about Cassiopeia cannot be completed without mentioning the supernova, which was observed by the famous astronomer Tycho Brahe in 1572. This supernova is one of 8 supernovae for which historical information has been preserved. So, it was November 1572... “One evening,” writes Tycho Brahe, “when I, as usual, was examining the sky, the appearance of which was well known to me, I, to my indescribable surprise, saw near the zenith in Cassiopeia an extraordinary bright star magnitude.Struck by the discovery, I did not know whether to believe my own eyes.

The new star did not have a tail, it was not surrounded by any nebula, it was in all respects similar to other stars of the first magnitude... In terms of its brilliance, it could only be compared with Venus, when the latter is at the closest distance from the Earth. People gifted with good eyesight could discern this star in a clear sky during the day, even at noon. At night, with a cloudy sky, when other stars were hidden, the new star remained visible through fairly thick clouds.

Starting from December 1572, its shine began to decrease... Transition from 5 stars. led to 6m star led occurred between December 1573 and February 1574. The following month the new star disappeared, having shone for seventeen months and leaving no trace visible to the naked eye."

In 1952, at the site of the explosion of this supernova, astronomers found a source of radio emission, and 8 years later its remnant was found in the optical range.

Cassiopeia in the northeastern sky at midnight on July 10, 2005.