Andromeda (constellation)

Andromeda 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).

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 88 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.

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.

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. ^*. 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.

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 alpha Andromedae. The lady's body is formed by the stars delta Andromedae, pi Andromedae, and beta Andromedae. Both alpha Andromedae and beta Andromedae are of second magnitude. Stars delta Andromedae and pi Andromedae represent the lady's shoulders, whereas star beta Andromedae represent's the lady's pelvis.

One of the lady's legs is formed by stars beta Andromedae, upsilon Andromedae, and gamma Andromedae: gamma Andromedae is of second magnitude and represents the lady's foot. The other leg is formed by stars beta Andromedae, mu Andromedae, nu Andromedae, phi Andromedae, and 51 Andromedae. Star 51 Andromedae 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 delta Andromedae, epsilon Andromedae, zeta Andromedae, and eta Andromedae, with star eta Andromedae representing one of her hands.

The other arm is formed by stars pi Andromedae, rho Andromedae, theta Andromedae, and iota Andromedae, with iota Andromedae corresponding to her other hand. Stars rho Andromedae, theta Andromedae , and sigma Andromedae represent the lady's elbow. The lady's hand at iota Andromedae is bound to a chain formed by the stars lambda Andromedae, kappa Andromedae, iota Andromedae, and omicron Andromedae. 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.

Reference

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

Notable and named stars

< سرة الفرس surrat^* al-faras Navel of the steed (mare) (سرة alone is surrah)
Alpha2 Canum Venaticorum type variable star

< ? al-maraqq The loins

< ? ؟ الارض al-^{c^{anāq al-arđ̧}} The "earth-kid", (a mustelid)
double star; component magnitudes: 2.26, 4.84

spectroscopic quadruple star

RS Canum Venaticorum type variable star

RS Canum Venaticorum type variable star

has three planets

< 軍南門 (Mandarin jūnnánmén) The south gate of the camp
Keun Nan Mun shared with χ Andromedae

< الذيل að-ðayl The train (of a garment) The tail

< 軍南門 (Mandarin jūnnánmén) The south gate of the camp
Keun Nan Mun shared with φ Andromedae

has Promethium lines in its spectrum.
Alpha2 Canum Venaticorum type variable star

nearby
double star; component magnitudes: 8.08, 11.06
flare star

nearby

1885 supernova in the Andromeda Galaxy.

BD	F	Names and other designations	Mag.	Ly away
α	21	Alpha Andromedae, Alpheratz, Alpherat, Al'faret, Al'ferats, Sirrah, Sirah, Sirrakh	2.06	97.1
β	43	Beta Andromedae, Mirach, Merach, Mirac, Mirak, Mirakh, Merak, Mirar, Mirath, Mirax, El Mizar, Al Mizar	2.07	199
γ¹^,²	57	Gamma Andromedae, Almach, Almaak, Alamak, Almak, Almaach, Alamac, Al'mak	2.26	355
δ	31	Delta Andromedae	3.27	101
	51	51 Andromedae	3.59	174
ο	1	Omicron Andromedae	3.62	692
λ	16	Lambda Andromedae	3.81	84.2
μ	37	Mu Andromedae	3.86	136
ζ	34	Zeta Andromedae	4.08	181
υ	50	Upsilon Andromedae	4.09	43.9
κ	19	Kappa Andromedae	4.15	170
φ	42	Phi Andromedae, Keun Nan Mun	4.26	740
ι	17	Iota Andromedae	4.29	503
ε	30	Epsilon Andromedae	4.34	169
π	29	Pi Andromedae	4.34	660
η	34	Eta Andromedae	4.40	243
σ	25	Sigma Andromedae	4.51	141
ν	35	Nu Andromedae	4.53	680
	7	7 Andromedae	4.53
θ	24	Theta Andromedae	4.61	253
	3	3 Andromedae	4.64
	65	65 Andromedae	4.73
	58	58 Andromedae	4.78
	8	8 Andromedae	4.82
ω	48	Omega Andromedae	4.83	92.3
b	60	60 Andromedae	4.84
ξ	46	Xi Andromedae, Adhil	4.88	196
τ	53	Tau Andromedae	4.96	680
ψ	20	Psi Andromedae	4.97	1310
χ	52	Chi Andromedae, Keun Nan Mun	5.01	242
	22	22 Andromedae	5.01
	41	41 Andromedae	5.04
	2	2 Andromedae	5.09
ρ	27	Rho Andromedae	5.16	160
	64	64 Andromedae	5.19
	28	28 Andromedae	5.20
	14	14 Andromedae	5.22
A	49	49 Andromedae	5.27
	4	4 Andromedae	5.30
	32	32 Andromedae	5.30
c	62	62 Andromedae	5.31
	18	18 Andromedae	5.35
	55	55 Andromedae	5.42
	11	11 Andromedae	5.44
	36	36 Andromedae	5.46
	15	15 Andromedae	5.55
	63	63 Andromedae	5.57
	47	47 Andromedae	5.60
	44	44 Andromedae	5.67
	5	5 Andromedae	5.68
	56	56 Andromedae	5.69
	23	23 Andromedae	5.71
	13	13 Andromedae	5.75
	12	12 Andromedae	5.77
	45	45 Andromedae	5.80
	10	10 Andromedae	5.81
	6	6 Andromedae	5.91
	39	39 Andromedae	5.95
	9	9 Andromedae	5.98
	59	59 Andromedae	6.09
	26	26 Andromedae	6.10
	66	66 Andromedae	6.16
		HR 465, GY Andromedae	6.36	455
	59	59 Andromedae	6.82
		Groombridge 34, GQ Andromedae, GX Andromedae	8.01	11.62
		Ross 248	12.29	10.32
		S Andromedae, Supernova 1885		2.9 million

Source: The Bright Star Catalogue, 5th Revised Ed., The Hipparcos Catalogue, ESA SP-1200

Stars with planets

Star	Planet	Distance (ly)	Discovered
HD 13507	HD 13507 b	85.45	2002
HD 3346	HD 3346 b	655.58	1996
HD 3346	HD 3346 c	655.58	1996
HD 8673	HD 8673 b	124.75	2005
Upsilon Andromedae	Upsilon Andromedae b	52	1996
	Upsilon Andromedae c	52	1999
	Upsilon Andromedae d	52	1999

External links

Andromeda constellation

Gourt Home::Gourt :: Andromeda (constellation)