Serpens

From Freepedia

Serpens
Image:Serpens constellation map.png click for larger image
Abbreviation	Ser
Genitive	Serpentis
Symbology	the Snake
Right ascension	Serpens Caput: 16 h Serpens Cauda: 18 h
Declination	Serpens Caput: +10° Serpens Cauda: −5°
Area	637 sq. deg. Ranked 23rd
Number of stars (magnitude < 3)	1
Brightest star	α Ser (Unukalhai) (App. magnitude 2.63)
Meteor showers
Bordering constellations	Serpens Caput: Corona Borealis Boötes Virgo Libra Ophiuchus Hercules Serpens Cauda: Aquila Ophiuchus Sagittarius Scutum
Visible at latitudes between +80° and −80° Best visible at 21:00 (9 p.m.) during the month of July

Serpens (the snake) is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy. Among the modern constellations it is unique in sometimes being split into two pieces, Serpens Caput (representing the head of the snake) to the west and Serpens Cauda (representing the tail) to the east. Between these two pieces lies the constellation of Ophiuchus, the serpent holder.

1 Notable features
2 Notable deep-sky objects
3 Mythology
4 Notable and named stars
5 See also
6 External links

Notable features

Since Serpens is regarded as being one constellation despite being split into two halves, the ordering of Bayer designations goes in order of brightness among both constellations.

Only one of the stars in Serpens is brighter than third magnitude, so the constellation is not easy to perceive. α Serpentis, named Unukalhai, is in the head part. δ Serpentis, also in the head, is a double star only 27 light-years from Earth. θ Serpentis, in the tail, is also double.

Stars in the head include α, β, γ, δ, ε, ι, κ, λ, μ, π, ρ, σ, τ, χ and ω Serpentis. Stars in the tail include ζ, η, θ, ν, ξ, and ο Serpentis.

Notable deep-sky objects

M5, a globular cluster approximately 8° southwest of α Serpentis in the head, is among the most beautiful in the sky.

M16 is a young open cluster associated with the Eagle Nebula, a diffuse nebula which is a region of current star formation in the tail.

Part of the Milky Way passes through the tail, as illustrated by the shaded regions of the star map.

Mythology

Serpens is the snake being grasped by Ophiuchus, the Snake-Handler, and is thus very closely associated with it. Both were listed as constellations by Ptolemy. Originally, Serpens and Ophiuchus were considered a single Snake-Holder constellation, out of which developed an associated myth of the founding of medicine.

Notable and named stars

BD	F	Names and other designations	Mag.	Ly away	Comments
α	24	Alpha Serpentis, Unukalhai, Unukalhay, Unuk al Hay, Unuk Elhai, Unuk, Cor Serpentis	2.63	73.2	عنق الحية ^{c^{unuq[u] al-ħayya[h]}} [The] neck of the snake cor serpentis The heart of the snake
η	58	Eta Serpentis	3.23	61.8
μ	32	Mu Serpentis	3.54	156
ξ	55	Xi Serpentis	3.54	105
β	28	Beta Serpentis, Chow	3.65	153	周 (Mandarin zhōu) The Zhou dynasty
ε	37	Epsilon Serpentis	3.71	70.3
δ	13	Delta Serpentis	3.80	210	Delta Scuti type variable star
γ	41	Gamma Serpentis	3.85	36.3
θ^1,2	63	Theta Serpentis, Alya, Alga	4.03	132	? al-alyah The fatty-tail sheep?
κ	35	Kappa Serpentis	4.09	348
ο	56	Omicron Serpentis	4.24	168	Delta Scuti type variable star
ν	53	Nu Serpentis	4.32	193
λ	27	Lambda Serpentis	4.42	38.3
ι	21	Iota Serpentis	4.51	192
ζ	57	Zeta Serpentis	4.62	75.7
ρ	38	Rho Serpentis	4.74	395
π	44	Pi Serpentis	4.82	177
σ	50	Sigma Serpentis	4.82	89.2
	5	5 Serpentis	5.04
b	36	36 Serpentis	5.09
	10	10 Serpentis	5.15
τ¹	9	Tau-1 Serpentis	5.16	920
ω	34	Omega Serpentis	5.21	263
d	59	59 Serpentis	5.21
	16	16 Serpentis	5.26
	3	3 Serpentis	5.32
χ	20	Chi Serpentis	5.34	228	Alpha2 Canum Venaticorum type variable star
	6	6 Serpentis	5.35
c	60	60 Serpentis	5.38
A²	25	25 Serpentis	5.39
A¹	11	11 Serpentis	5.50
M	1	1 Serpentis	5.51
	30	30 Serpentis	5.53
φ		Phi Serpentis	5.54	227
	64	64 Serpentis	5.56
	62	62 Serpentis	5.58
	4	4 Serpentis	5.62
	45	45 Serpentis	5.63
	47	47 Serpentis	5.69
υ	31	Upsilon Serpentis	5.71	252
	2	2 Serpentis	5.71
e		e Serpentis	5.76
τ⁷	22	Tau-7 Serpentis	5.80	174
ψ	23	Psi Serpentis	5.86	47.9
τ⁵	18	Tau-5 Serpentis	5.93	160
	61	61 Serpentis	5.93
τ⁶	19	Tau-6 Serpentis	6.00	451
	39	39 Serpentis	6.07
	43	43 Serpentis	6.07
τ³	15	Tau-3 Serpentis	6.10	414
	8	8 Serpentis	6.11
τ⁸	26	Tau-8 Serpentis	6.15	321
τ²	12	Tau-2 Serpentis	6.22	431
	40	40 Serpentis	6.28
	7	7 Serpentis	6.29
τ⁴	17	Tau-4 Serpentis	6.51	520	Semiregular variable
	14	14 Serpentis	6.51
	49	49 Serpentis	6.68
	46	46 Serpentis	6.74
		HD 168443	6.92	123.5	has 2 planets
		HD 168746	7.95	140.6	has a planet
		Gliese 710	9.66	63.0	future encounter at 1.1 ly