Andromeda (constellation)

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Andromeda

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Abbreviation:	And
Genitive:	Andromedae
Symbology:	Andromeda, the Chained Maiden
Right ascension:	1 h
Declination:	+40°
Area:	722 sq. deg. (19th)
Main stars:	4, 18
Bayer/Flamsteed stars:	63
Stars with known planets:	2
Bright stars:	3
Nearby stars:	5
Brightest star:	α And (Alpheratz) (2.1m)
Nearest star:	Ross 248 (10.32 ly)
Messier objects:	3
Meteor showers:	Andromedids (Bielids)
Bordering constellations:	Perseus Cassiopeia Lacerta Pegasus Pisces Triangulum
Visible at latitudes between +90° and −40° Best visible at 21:00 (9 p.m.) during the month of November

Andromeda (IPA: /ˌanˈdrɒmədə/) is a constellation named for the princess Andromeda (which is Greek for Ruler over men), a character in Greek mythology. The constellation is in the northern sky near the constellation Pegasus. It is most notable for containing the Andromeda Galaxy. It is sometimes called "The Chained Maiden" in English.

Corresponding Chinese constellations in Andromeda are Flying serpent (螣蛇), Celestial stable (天廄), Wall (壁), Legs (奎), Southern military gate (南軍門) and Great general of the heaven (天大将軍).

Contents 1 Notable features 2 Notable deep sky objects 3 Mythology 4 Graphic visualization 5 See also 6 References 7 External links

[edit] Notable features

The brightest star in the constellation is Alpheratz (Sirrah in the image), which marks her head, Bayer designation Alpha Andromedae. Formerly considered common to Andromeda and Pegasus, as confirmed by its name, "navel of the horse", it was also designated δ Pegasi. With α, β, and γ Pegasi it forms an asterism called the Great Square of Pegasus.

β Andromedae is called Mirach, the girdle. It is 200 light years distant and of magnitude 2.1.

γ Andromedae, or Almach, is found at the tip of the southern leg of the big "A". It is a beautiful multiple star with contrasting colours.

υ Andromedae has a planetary system with three confirmed planets, 0.71 times, 2.11 times, and 4.61 times the mass of Jupiter.

[edit] Notable deep sky objects

The most famous deep sky object in Andromeda is M31, the Andromeda Galaxy, one of the most distant objects visible to the naked eye (M33 is slightly farther). It is an enormous spiral galaxy much like ours. To find the galaxy, draw a line between β and μ Andromedae, and extend the line approximately the same distance again from μ.

[edit] Mythology

If fainter stars, visible to the naked eye, in the constellation are considered, then the constellation takes the form of a stick-figure woman, with a prominent belt (as has the constellation Orion), where one arm has something long attached to it, giving the appearance of a female warrior holding a sword. This, together with other stars in the zodiac sign of Aries (part of Pisces, and the Pleiades), may be the origin of the myth of the girdle of Hippolyte, which forms part of The Twelve Labours of Herakles.

However, by including still fainter stars, the attachment extends in a different direction, giving the appearance of a maiden held by a chain.^[1] Together with other constellations nearby (Cassiopeia, Cepheus, Cetus, Pegasus, and Perseus), this may be the source of the myth of the Boast of Cassiopeia, with which it is usually identified.

[edit] Graphic visualization

The stars of the constellation Andromeda can be connected in an alternative way, which graphically shows a chained lady.

The lady's head is represented by the star α And. The lady's body is formed by the stars δ And, π And, and β And. Both α And and β And are of second magnitude. Stars δ And and π And represent the lady's shoulders, whereas star β And represent's the lady's pelvis.

One of the lady's legs is formed by stars β And, υ And, and γ And: γ And is of second magnitude and represents the lady's foot. The other leg is formed by stars β And, μ And, ν And, φ And, and 51 And. Star 51 And represents one of the lady's feet, which is being yanked by the hand of neighboring constellation Perseus, who is trying to liberate Andromeda.

One of the lady's arms is formed by stars δ And, ε And, ζ And, and η And, with star η And representing one of her hands.

The other arm is formed by stars π And, ρ And, θ And, and ι And, with ι And corresponding to her other hand. Stars ρ And, θ And , and σ And represent the lady's elbow. The lady's hand at ι And is bound to a chain formed by the stars λ And, κ Abd, ι And, and ο And. According to myth, Andromeda was bound by this chain to a rock by the sea by order of her father, Cepheus, the king of Aethiopia, who wanted to appease the god Poseidon who had been angered by Cassiopeia's boasting about her own beauty, and consequently Poseidon sent one of his underlings: Cetus, the whale, to ravage the coast of Aethiopia. Cepheus, Cassiopeia's husband, had Andromeda bound by chain to a rock by the sea so that Cetus would devour Andromeda, appeasing Poseidon, thereby preventing any further ravaging of the coast of Aethiopia by Cetus. But the hero Perseus took Andromeda out of her chains and then flew with her on his winged horse, Pegasus, away from the scene of her sacrificial imprisonment. He subsequently married her. For more details on this myth, see the Boast of Cassiopeia.

[edit] See also

• List of stars in Andromeda

[edit] References

1. ^ http://borghetto.astrofili.org/costellazioni/andromeda.JPG

• H. A. Rey, The Stars — A New Way To See Them. Enlarged World-Wide Edition. Houghton Mifflin, Boston, 1997. ISBN 0-395-24830-2.

[edit] External links

• The Deep Photographic Guide to the Constellations: Andromeda
• NightSkyInfo.com: Constellation Andromeda
• Traditional astrological talisman of Andromeda
• WIKISKY.ORG: Andromeda