Andromeda Constellation aka The Chained Maiden
The constellation of the Chained Maiden is named after princess Andromeda of Ethiopia. Her father was King Cepheus and her mother was Queen Cassiopeia. This constellation belongs to the Perseus family. Other constellations in that family are Perseus, Cassiopeia, Cepheus, Pegasus, and Cetus. They are all tied up in the same mythology that led to their rightful places in the night sky.
The constellations of Auriga, Lacerta, and Triangulum were added to the Perseus family of constellations because they are located near the other ones mentioned. All of them can be seen in the north celestial hemisphere to declination −30° in the south.
The Andromeda constellation is among the 48 constellations included in the catalogue of Ptolemy in the second century. It occupies an area of 722 square degrees in the sky, making it one of the largest. In fact, it ranks the 19th largest constellation among the 88 modern constellations of today!
What does Andromeda Look Like?
Different sources have different versions of the form of this constellation. Some definitely look like a person with chains on both hands, like this:
Others have a trickier version of the Chained Maiden of the sky like the one below:
For those who prefer the much simpler one, below is an easier form of the mythological Princess of Ethiopia:
As you can see, we can make sense of the Andromeda constellation by the different ways we can connect its stars. Since only the boundaries of the constellation are set and not their form, we can always use our imaginations to form Andromeda in our night sky!
What’s In A Name?
Other English names for Andromeda are “the Chained Woman” and “the Chained Lady”. In reference to its Greek Mythology, it is called Persea which means “Perseus’s wife” and Cepheis, meaning “Cepheus’s daughter”. The name “Chained Maiden” was used as the English name of the constellation by the International Astronomical Union (IAU). The same name is called Mulier Catenata in the Latin language and al-Mar’at al Musalsalah in Arabic.
Where To See the Andromeda Constellation
Andromeda has the coordinates of one hour right ascension and 40 degrees declination in the celestial sphere. From here on Earth, it is mostly seen in the northern hemisphere between latitudes +90° and −40°. The constellation dips in the horizon in places farther south of −40° so it is not seen by observers in those locations.
Andromeda and Her Neighbors
If we already know how to spot other constellations, then identifying Andromeda can become easier. It is surrounded by Perseus the Hero, Cassiopeia the Seated Queen, Lacerta the Lizard, Pegasus the Winged Horse, Pisces the Fishes, and Triangulum the Triangle. Finding one constellation relative to the others brings connectedness among the things that make up our sky.
Andromeda and the Great Square of Pegasus
The Great Square of Pegasus is a famous asterism in the Northern Sky in autumn. It is made up of four equally bright stars. If we find it, we can easily spot Andromeda because she is connected to the Great Square as if they are one!
When To See the Andromeda Constellation
Andromeda is a seasonal constellation. That means we cannot see it in the night sky all year long. We can only see the celestial Chained Maiden during autumn, that is, from September 1 to November 30 following the meteorological season. The time to see it best is during the month of November at about 9 pm.
Andromeda and Her Stars
Since the constellation of Andromeda is a large constellation, there are many interesting stars within its boundaries. It has 16 main stars, more than four of which are formally named. There are 12 stars in this constellation that are discovered to have planets.
1. Alpheratz (α Andromedae)
Alpha Andromedae is officially called Alpheratz. It marks the head of Andromeda in the night sky. Alpheratz is a binary star system with a combined apparent magnitude of about 2.06, making it the brightest star in the Andromeda constellation. This A0p class binary is also the brightest mercury-manganese star known. The components of this system are a spectroscopic binary that orbits each other in a period of 96.7 days. This system is 97 light-years away from our Sun.
● Primary Component
It is the brighter of the pair. This B-type star is unique because it contains high levels of elements especially mercury and manganese. Its mass is about 3.6 solar masses. It is much brighter than the Sun, having more than 200 solar luminosity.
● Secondary Component
The secondary component is an early A-type star that is fainter. It has about 1.8 solar masses. Its luminosity is said to be 10 times the Sun’s luminosity.
In 1781, William Herschel discovered a visual companion of the binary stars in Alpha Andromedae. It was called ADS 94 B. It is a G-type star that is not seen with the naked eye since its apparent magnitude is about 10.8. Also, it is located farther than the binary as it is about 1,360 light-years away.
Traditionally, Alpheratz was also called Sirrah (Delta Pegasi). Since this is one of the stars that form the Great Square of Pegasus, there was a time when it was a part of both the constellations of Andromeda and Pegasus. The name Sirrah was from the Arabic surrat al-faras, meaning “the navel of the mare”.
To avoid confusion, the International Astronomical Union (IAU) standardized the names and boundaries of the constellations. It was finally decided that the star will only be a part of the Andromeda constellation, officially naming it Alpheratz.
2. Mirach (β Andromedae)
Mirach is the official name of Beta Andromedae. It marks the left hip of the Chained Lady, Andromeda. The official name has its origin from the Arabic phrase al-Maraqq which means “the loins” or “the loincloth”, from the Almagest.
Mirach is a suspected semiregular variable star and its apparent magnitude changes between +2.01 to +2.10. The stellar classification of this red giant star is M0 III. It is about 197 light-years distant from the Sun. This star is just seven arc minutes away from NGC 404, a galaxy which is also called Mirach’s Ghost.
3. Gamma Andromedae (γ Andromedae)
Gamma Andromedae is a quadruple star system. It is said to be 350 light-years away from us. By looking at the constellation chart, Gamma Andromedae marks one of the legs of the Princess of Ethiopia.
The traditional name of the entire system was Almach. It was decided by the Working Group on Star Names (WGSN) that the name be officially designated to the primary star component of this multiple star system. The name was from the Arabic al-‘anāq, meaning “the caracal” or “the desert lynx”. Other variations of this name are Almaack, Almaach, Almak, Almaak, or Alamak.
The main components of this star system are called Gamma Andromedae A and Gamma Andromedae B from the Washington Multiplicity Catalog (WMC). It takes about 5,000 years for them to complete their orbit.
● Gamma Andromedae A (γ1 Andromedae)
Gamma Andromedae A is officially named Almach. It can be seen by the naked eye since it has an apparent magnitude of about 2.26. In fact, it is the third brightest object in the Andromeda constellation. This giant star is a K-type star.
● Gamma Andromedae B (γ2 Andromedae)
Gamma Andromedae B is a double star with about 5.5 apparent magnitude. Its other component is Gamma Andromedae C, a 6th magnitude A-type star in the main sequence.
Interestingly, Gamma Andromedae B is also a spectroscopic binary. It is composed of main-sequence stars that have an orbital period of 2.67 days. So in general, we can say that Gamma Andromedae B is in itself a triple star system!
4. Delta Andromedae (δ Andromedae)
Delta Andromedae is a spectroscopic binary. It is about 105.5 light-years away from our planet. The combined apparent magnitude is about 3.28, so we can see it in the naked eye. The main component is a K-type giant star and the secondary is either a dwarf or a main-sequence star in the G or K class.
By looking at the chart, we can see that Delta Andromedae is one of the stars that form the body of the Chained Woman.
5. Epsilon Andromedae (ε Andromedae)
Epsilon Andromedae is a G-type giant. It has an apparent magnitude of 4.4 and a distance to the Sun that is about 155 light-years. The mass of this star is approximately the same as our Sun’s.
6. Zeta Andromedae (ζ Andromedae)
Zeta Andromedae is a spectroscopic binary located roughly 189 light-years from Earth. It is an RS Canum Venaticorum variable. Variable stars of this type are close binaries with starspots. The apparent magnitude of this system varies from +3.92 to +4.14. The primary component, designated Zeta Andromedae Aa, is a K-type giant star. There are visual companions discovered to the binary.
7. Eta Andromedae (η Andromedae)
Eta Andromedae is a spectroscopic binary with an apparent magnitude of about 4.403. The components of this system are either subgiants or giant stars in the G class. They have an orbital period of 115.7 days. An 11th magnitude visual companion was discovered to this system.
8. Theta Andromedae ( θ Andromedae)
Theta Andromedae is a binary star system. The primary component has an apparent magnitude of about +4.61. It is a dwarf main-sequence with a white hue since it is an A-type star. The secondary component is also believed to be an A-type star.
9. Iota Andromedae (ι Andromedae)
Iota Andromedae is named 17 Andromedae in the Flamsteed designation. It is called kaf al-musalsala in a star catalogue, which is translated Manus Catenata in Latin. The translation means “palm of chained woman” in English which is a good description of the star’s position if we look at the Andromeda constellation.
This single star appears to have a blue-white hue in the night sky since it has a stellar classification of B8 V. It is a variable star with an apparent magnitude of about +4.29. It has a distance of about 500 light-years from the Sun.
10. Kappa Andromedae (κ Andromedae)
Kappa Andromedae has an apparent magnitude of 4.1 so we can see it in the naked eye in a dark sky. This blue-white hued B-type star is becoming a subgiant. It is 168 light-years away from Earth. It is a fast rotator that has 2.3 times the Sun’s radius.
The star is also labeled Kappa Andromedae A to avoid confusion with Kappa Andromedae b, a planet discovered in the system. This planet has a mass that is 13.616 times the mass of the planet Jupiter.
11. Lambda Andromedae (λ Andromedae)
Lambda Andromedae is a spectroscopic binary with an apparent magnitude of +3.8. It is 86.1 light-years away from our planet. The primary component is a yellow-hued G-type star with a mass similar to the Sun’s. This evolved star is already in the subgiant or giant stage. It is 23 times more luminous than the Sun. Stellar spots are sometimes present in the star because it is an RS Canum Venaticorum variable.
12. Mu Andromedae (μ Andromedae)
Mu Andromedae is a white-hued main-sequence star with 3.87 as its apparent magnitude. If we look at the constellation chart of the Andromeda constellation, it is located between the famous Andromeda Galaxy and Mirach (Beta Andromedae). Its luminosity is about 21 times that of the Sun. It also has twice the Sun’s mass. It was found out that it is actually a binary star. The components have an orbital period of 550.7 days. The star system is located 130 light-years from us.
13. Nu Andromedae (ν Andromedae)
Nu Andromedae is a binary star system. It is located very close to the Andromeda Galaxy. The primary in the spectroscopic binary is a main-sequence star of B5 V stellar classification while the secondary component is an F-type main sequence. They orbit each other in a period of 4.28 days. Nu Andromedae has an apparent magnitude of 4.5. It is about 620 light-years from us.
14. Adhil (ξ Andromedae)
Xi Andromedae is a K-type subgiant star. The apparent magnitude of this star is about +4.9. Its traditional name was Adhil which also became its official name. The name is Arabic in origin, from the word að-ðayl which literally translates to “the trail”, meaning that of the train.
Adhil has a mass that is 2.5 times that of the Sun and a radius that is 10 times more than it. This orange-hued star is 214 light-years away from our Sun.
15. Omicron Andromedae (ο Andromedae)
Omicron Andromedae is a variable multiple star system. Overall, it is a B-type giant. This star marks one of Princess Andromeda’s chains. Its magnitude varies between +3.58 to +3.78. It is 692 light-years away from our planet. The system is made up of two close pairs of stars, making it a quadruple star system.
● Components Aa and Ab
The orbital period of components Aa and Ab is 5.6 years. The variable, component Aa, is the primary star in the system. It is the most massive as well as the brightest among the four.
● Components Ba and Bb
Component B is a spectroscopic binary. It is thought to be an A-type system.
16. Pi Andromedae (π Andromedae)
Pi Andromedae is a fourth magnitude spectroscopic binary. It is one of the stars that mark the body of Andromeda in the constellation. The components are B-type stars in the main sequence. It takes 143.6 days for them to complete their orbit. A third star of 8.6 magnitude was discovered in the system. A companion of 11th magnitude was also discovered, though it is just situated in our line of sight. Pi Andromedae is about 600 light-years away from us.
17. Rho Andromedae (ρ Andromedae)
Rho Andromedae is an F-type giant or subgiant. It is hardly visible to the naked eye, especially in urban areas because it has an apparent magnitude of +5.19. It has a radius more than three times that of the Sun. Rho Andromedae is also more luminous than our Sun by about 20 times. It is said to be 1.3 billion years old already. It is about 158 light-years away from Earth.
18. Sigma Andromedae (σ Andromedae)
Sigma Andromedae is a main-sequence star having an apparent magnitude of +4.5. It has a stellar classification of A2 V. About 0.08 of its brightness is reduced because of gas and dust between our line of sight to this star. The radius of Sigma Andromedae is 2.1 times that of the Sun. It is radiating with a luminosity of 26 Suns. This star is estimated to be 450 million years old. It is 135 light-years away from us.
19. Tau Andromedae ( τ Andromedae)
Tau Andromedae is a B-type giant star. We can see this fifth magnitude star faintly in the naked eye. The extinction caused by gas and dust results in a reduced magnitude by about 0.24 in Tau Andromedae. It has a luminosity that is 851 times that of the Sun. It is situated 710 light-years from our planet.
20. Upsilon Andromedae (υ Andromedae)
Upsilon Andromedae is an extraordinary star system. It has a multiple-planet system in its multiple star system! It is relatively close to our Solar System as it is 44 light-years away from Earth.
● Upsilon Andromedae A (Titawin)
Titawin is the official name of the primary star in the Upsilon Andromedae star system. It has an apparent magnitude of +4.09. It is an F-type dwarf star that has about 1.3 solar masses. Titawin is estimated to be 3.1 billion years old.
Four planets are orbiting Titawin. They are Upsilon Andromedae b (formally named Saffar), Upsilon Andromedae c (formally named Samh), Upsilon Andromedae d (formally named Majriti), and Upsilon Andromedae e.
● Upsilon Andromedae B and C
Upsilon Andromedae B and C are both companion stars of Titawin. We cannot see them in the naked eye. The former has a 12.6 magnitude while the latter has a magnitude of 10.3.
● Upsilon Andromedae D
Upsilon Andromedae D is a close companion to Titawin. It is also the only one that is related to the primary star physically. This star is a red dwarf of 13th magnitude.
21. Phi Andromedae (φ Andromedae)
Phi Andromedae is a binary star. This pair completes their orbit at around 554 years. The primary is a B-type main-sequence star that is also a fast rotator. The fainter secondary component is also a main-sequence star with the stellar classification of B9 V. Overall, the apparent visual magnitude of the system is 4.25. It is 720 light-years from Earth.
22. Chi Andromedae (χ Andromedae)
Chi Andromedae is a suspected spectroscopic binary. It has an apparent magnitude of +5.2. The primary is a G-type giant star. Its luminosity is about 47 times that of the Sun. Chi Andromedae is about 250 light-years away from Earth
23. Psi Andromedae (ψ Andromedae)
Psi Andromedae is a triple star system though not much is still known about the other components. The primary is G-type supergiant. The secondary component is a B-type star. Astronomers are yet to find out about the orbital arrangement of the Psi Andromedae. The system has an overall apparent magnitude of 4.95. It is estimated to be 1,000 light-years from Earth.
24. Omega Andromedae (ω Andromedae)
Omega Andromedae is a binary star system. The primary is an F-type star as well as the secondary. The two are separated by 0.669 arcseconds. Omega Andromedae is said to be 93.3 light-years from Earth. It has an apparent magnitude of +4.83.
25. Nembus (51 Andromedae)
Nembus marks the right leg of Princess Andromeda. Known as 51 Andromedae in the Flamsteed designation, Nembus is a giant star in the K class. It is one of the brightest stars in the constellation of Andromeda. The age of this star is approximately 1.7 billion years. Its mass is 1.8 times that of the Sun. It has a luminosity of about 142 Suns. Nembus has an apparent magnitude of about +3.59. It has an estimated distance of roughly 169 light-years from us.
Deep-sky Objects in Andromeda Constellation
The Andromeda constellation does not only have many interesting stars and planets within its borders, it also has numerous deep-sky objects.
Messier 31 (Andromeda Galaxy)
We have heard about the Andromeda galaxy many times before. It is also called Messier 31 and NGC 224. This famous deep-sky object in the constellation of the Chained Maiden is about 2.2 to 2.5 million light-years away from us. Even with that distance, we can still see it in the naked eye in a dark sky because the apparent magnitude of this galaxy is 3.4. In fact, it is the most distant object we can see without using any equipment other than our eyes!
The Great Galaxy of Andromeda is among the brightest of the Messier objects. It is also a spiral galaxy just like the Milky Way but it is larger than our galaxy. It is the largest in the Local Group of galaxies, where the Milky Way also belongs. Astronomers have predicted a collision between the Andromeda Galaxy and the Milky Way in about four billion years. Here is a video that easily shows and explains how it happens.
Satellites of Andromeda Galaxy
Messier 31 or the Andromeda Galaxy has many satellite galaxies. The two main satellites are M32 and M110. Let us learn about them.
● Messier 32
M32 is also known as NGC 221. It is an elliptical galaxy about 2.5 million light-years from Earth. It has an apparent magnitude of 8.1, so we cannot see it in the naked eye but using at least a medium-sized telescope. M32 was discovered by French astronomer Guillaume Le Gentil in 1749.
In the image above from the Hubble Space Telescope, about 8,000 blue stars swarm around the core of M32. This ultraviolet light is from old stars that are burning helium instead of hydrogen.
● Messier 110
M110 is known as NGC 205 in the New General Catalogue. It is the largest and brightest satellite of the Andromeda Galaxy. This dwarf elliptical galaxy is approximately 15,000 light-years across. M110 is a member of the Local Group and contains young stars. The size of this galaxy is similar to that of the Magellanic Clouds.
How to Find the Andromeda Galaxy
The Great Galaxy of Andromeda is just near the constellation of the Chained Maiden in the night sky. We can use the stars in this constellation, as well as the neighboring constellations, to spot it. Here are the ways we can do it.
1. Using the W-shaped Cassiopeia
The W shape of Cassiopeia is hard to miss. The brightest star in this constellation is the star Schedar. It is located in one of the vertices of the W. If we draw a line from this star, pointing to the body of the Andromeda constellation, it will lead us to the Andromeda Galaxy.
2. Using Other Stars in the Andromeda Constellation
We have learned about the stars in the constellation of Andromeda. If we are going to draw a line between Mirach and Mu Andromedae, extending it to the latter’s side, we can locate Messier 31.
NGC 891 (Caldwell 23)
NGC 891 is called Caldwell 23 in the Caldwell Catalogue. Some call it the Silver Sliver Galaxy. It is located 30 million light-years from the Andromeda constellation. We can see it using small telescopes. From here on Earth, it looks edge-on just like the photo above. This galaxy looks similar to the Milky Way galaxy, with the central bulge darkened by cosmic dust.
NGC 752 (Caldwell 28)
NGC 752 is also known as Caldwell 28. It is an open cluster in the Andromeda constellation discovered by Caroline Herschel. It is 1,300 light-years distant from our planet.
NGC 7662 (Blue Snowball Nebula)
NGC 7662 is also called Caldwell 22 but is more famously known as the Blue Snowball Nebula. This planetary nebula is roughly 2,500 light-years away from Earth. It has an apparent magnitude of +8.6. It can be seen during autumn in the Northern Hemisphere and the spring season in the Southern Hemisphere.
NGC 404 (Mirach’s Ghost)
NGC 404 is nicknamed Mirach’s Ghost. It is an 11th magnitude field galaxy located 11 million light-years from our planet. We can see it using small telescopes. This galaxy is usually outshined by the glare of the giant star Mirach, hence the nickname Mirach’s Ghost. If viewed using ultraviolet light (as seen on the picture above, right), a blue ring containing new stars can be seen in the galaxy.
Meteor Showers Related to Andromeda
The Andromedids meteor shower is believed to have its radiant in the constellation of the Chained Maiden. Many closely link it to Biela’s Comet, which broke around the 1840s. This resulted in one of the most unforgettable meteor showers of the 19th century, illustrated above. The Andromedids shower is diffuse and slow. It is seen in the month of November.
Mythology Related to Andromeda Constellation
Andromeda was the fair princess of Ethiopia. She was the daughter of King Cepheus and Queen Cassiopeia. But the queen was a vain woman. She said that she is more beautiful than the Nereids (sea nymphs). This made the sea nymphs and the sea god Poseidon very angry.
Poseidon ravaged the kingdom by sending Cetus, a sea monster. King Cepheus became very worried that he consulted the Oracle of Ammon. According to the oracle, the only way to stop the total downfall of this land is to offer her daughter Andromeda to the sea monster. Andromeda’s father, King Cepheus, followed the advice and let his daughter be chained to a rock, awaiting her death with the savage sea monster. But fate was good to Andromeda because the hero Perseus saved her. The hero was back from his victory over the Gorgon Medusa. They later married and had children.
When Andromeda died, the goddess Athena honored her by placing her in the sky close to her loved ones, her husband Perseus, her mother Cassiopeia, and her father Cepheus.
Changes in Andromeda Constellation
Some of the stars that make up the Andromeda constellation today were part of a different constellation before. This constellation was called Honores Friderici or Gloria Frederica/ Frederici which means “Glory of Frederick”. German astronomer Johann Bode created it to honor the king of Prussia, Frederick the Great. This constellation is not among the 88 modern constellations of today and is no longer in use.
Honores Friderici was mostly situated in the constellation of Andromeda. It also occupied some areas of the constellations Cassiopeia, Cepheus, Lacerta, and Pegasus. It had some of the stars from these constellations as well. Most of the stars that made up Honores Friderici were from Andromeda. Its three brightest stars are now what we know as Kappa, Lambda, and Omicron Andromedae.