Ursa Major

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Ursa Major (Ursa Maior in Latin) is a constellation visible throughout the year in the northern hemisphere. Its name means Great Bear in Latin, and is associated with the legend of Callisto.

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

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Notable features

The seven brightest stars, located in the Bear's hindquarters and tail, form the well-known Big Dipper asterism. (In Britain, this asterism is known as the Plough.) Except for Dubhe and Alkaid, the stars of the Big Dipper all have proper motions heading towards a common point in Sagittarius. A few other such stars have been identified, and together they are called the Ursa Major Moving Group.

In addition to the Big Dipper, another asterism comes from Arab culture – the "leaps of the gazelle", a series of three pairs of stars:

ν and ξ Ursae Majoris, Alula Borealis and Australis, the "first leap";
λ and μ Ursae Majoris, Tania Borealis and Australis, the "second leap";
ι and κ Ursae Majoris, Talitha Borealis and Australis, the "third leap".

These stars are found along the southwest border of the constellation, the bear's toes.

W Ursae Majoris is the prototype of a class of contact binary variable stars, and ranges in magnitude between 7.75m and 8.48m.

47 Ursae Majoris has a planetary system with two confirmed planets, 2.54 times and 0.76 times the mass of Jupiter.

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Notable deep sky objects

Several bright galaxies are found in Ursa Major, including the pair M81 (one of the brightest galaxies in the sky) and M82 above the bear's head, and M101, a beautiful spiral northwest of η Ursae Majoris. Other galaxies in Ursa Major that appear in the Messier catalogue are M108 and M109, both spiral galaxies. All told, the constellation contains about 50 galaxies observable through telescopes available to the amateur astronomer, most of which are below 10th magnitude. The bright planetary nebula M97, also known as the "Owl Nebula" for its appearance in photographs, can be found along the bottom of the bowl of the Big Dipper. Of note as a curiosity more than an interesting deep sky object is M40, a double star that Messier nonetheless included in his catalogue.

The Hubble Deep Field is located to the northeast of δ UMa.

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History

Image:Ursa Major constellation Hevelius.jpg

Ursa Major was one of the 48 constellations listed by Ptolemy. It is one of the most widely-known constellations, having been mentioned by such poets as Homer, Spenser, Shakespeare, Tennyson and Bertrand Cantat. The Finnish epic Kalevala mentions it, and Vincent Van Gogh included its stars in his Starry Night Over the Rhone.

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Mythology

The constellation of Ursa Major has been seen by many distinct civilizations as a bear. In consequence, together with the nearby Ursa Minor, it formed the basis of the myth of Callisto.

In earlier times, Greek mythology did not consider Ursa Major a bear, and instead its 3 bright stars (situated in the tail) were seen as apples growing on a tree (sometimes represented by the fainter stars in the remainder of the constellation). At the same time, the stars of Ursa Minor were associated with the Hesperides. These two groups of stars, together with Libra, Boötes and Draco, may have inspired the myth of the apples of the Hesperides, one of The Twelve Labours of Hercules.

One of the few star groups mentioned in the Bible (Job 9:9; 38:32 – Orion and the Pleiades being others), Ursa Major was also pictured as a bear by both the Hebrews and most North American peoples. However, as bears do not have long tails, they considered Alioth, Mizar, and Alkaid to be either three cubs following their mother or three hunters. ("The Bear" was mistranslated as "Arcturus" in the Vulgate and the error persisted in the KJV. Later translations have corrected this.)

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Notable and named stars

BD
ε	77	Epsilon Ursae Majoris, Alioth	1.76	80.9	alyat Fat tail of the sheep
α	50	Alpha Ursae Majoris, Dubhe, Dubh, Dubb, Thahr al Dub al Akbar, Ak	1.81	124	< ظهر الدب الأكبر z̧ahr ad-dubb al-akbar Back of the greater bear
η	85	Eta Ursae Majoris, Benetnasch, Alkaid, Elkeid	1.86	101	< القائد البنات النعش al-qāid al-banāt an-na^c "The leader of the daughters of the bier" (the daughters of the bier, i.e. the mourning maidens, are the three stars of the handle of the Big Dipper, Alkaid, Mizar, and Alioth.)
ζ	79	Mizar, Zeta Ursae Majoris, Mizat, Mirza	2.23	78.2	< مئزر mi´zar girdle visual double star with Alcor
β	48	Beta Ursae Majoris, Merak, Mirak	2.34	79.4	< ? al-maraqq The loins (flank?) [of the bear]
γ	64	Gamma Ursae Majoris, Phad, Phecda, Phegda, Phekha, Phacd	2.41	83.7	< الفخذ الدب al-faxð al-dubb The thigh of the bear
ψ	52	Psi Ursae Majoris, Ta Tsun	3.00	147	< Name of chinese origin.
μ	34	Mu Ursae Majoris, Tania Australis, Alkafzah Australis	3.06	249	< القفزة الثانية al-qafzat aθ-θāniyah (or at-tāniyah) The second leap (of the gazelle) [القفزة by itself is al-qafzah] + austrālis southern Semiregular variable
ι	9	Iota Ursae Majoris, Talitha Borealis, Talita Borealis, Dnoces, Alphikra Borealis	3.12	47.7	< القفزة الثالثة al-qafzat aθ-θāliθah (or at-tālitah) The third leap (of the gazelle) + boreālis northern < second backwards < الفقرة الثالثة al-fiqra[h] The vertebra Double binary star.
θ	25	Theta Ursae Majoris, Al Haud, Sarir, Sarir Bonet?	3.17	44.0	< الحوض al-ħawđ̧ The pond/pelvis (which?) < سرير as-sarīr The couch/bed [of the dead]
δ	69	Delta Ursae Majoris, Megrez, Kaffa	3.32	81.4	< المغرز al-maghriz The root/insertion-point [of the bear's tail]
ο	1	Omicron Ursae Majoris, Muscida	3.35	184	< post-classical Latin musus "snout", "muzzle" Muscida shared with π¹^,² Ursae Majoris
λ	33	Lambda Ursae Majoris, Tania Borealis, Alkafzah Borealis	3.45	134	< القفزة الثانية al-qafzat aθ-θāniyah (or at-tāniyah) The second leap (of the gazelle) [القفزة by itself is al-qafzah] + boreālis northern
ν	54	Nu Ursae Majoris, Alula Borealis	3.49	421	< القفزة الأولى al-qafzat al-´ūla´ The first leap (of the gazelle) + boreālis northern
κ	12	Kappa Ursae Majoris, Talitha Australis, Al Kaprah, Alphikra Australis	3.57	423	< القفزة الثالثة al-qafzat aθ-θāliθah The third leap (of the gazelle) + austrālis southern Al Kaprah is a corruption of القفزة al-qafzah The leap < الفقرة الثالثة al-fiqra[h] The vertebra
h	23	23 Ursae Majoris	3.65	75.5
χ	63	Chi Ursae Majoris, Alkafzah, Alkaphrah, El Koprah	3.69	196	< القفزة al-qafzah The leap
υ	29	Upsilon Ursae Majoris	3.78	115	Delta Scuti type variable star
ξ	53	Xi Ursae Majoris, Alula Australis	3.79	28.8	< القفزة الأولى al-qafzat al-´ūla´ The first leap (of the gazelle) + austrālis southern binary star; component magnitudes: 4.4 + 4.9 RS Canum Venaticorum type variable star
g	80	Alcor, 80 Ursae Majoris, Saidak	3.99	81.2	< سها Al-Suha, the pious woman. Also a corruption of al-jawn "the black horse", originally applied to Mizar. Alcor is the rider of the "horse and rider" visual double star with Mizar
f	15	15 Ursae Majoris	4.46
	26	26 Ursae Majoris	4.47
d	24	24 Ursae Majoris	4.54
π²	4	Pi-2 Ursae Majoris, Muscida	4.59	252	< post-classical Latin musus "snout", "muzzle" Muscida shared with ο Ursae Majoris
	83	83 Ursae Majoris	4.63
ω	45	Omega Ursae Majoris	4.66	267
τ	14	Tau Ursae Majoris	4.67	122
ρ	8	Rho Ursae Majoris	4.74	287
	55	55 Ursae Majoris	4.76
σ²	13	Sigma-2 Ursae Majoris	4.80	66.7
e	18	18 Ursae Majoris	4.80
	36	36 Ursae Majoris	4.82
	78	78 Ursae Majoris	4.93
	56	56 Ursae Majoris	4.99
	46	46 Ursae Majoris	5.02
	47	47 Ursae Majoris	5.03	45.9	has two planets
	49	49 Ursae Majoris	5.06
	38	38 Ursae Majoris	5.12
	44	44 Ursae Majoris	5.12
σ¹	11	Sigma-1 Ursae Majoris	5.15	500
	27	27 Ursae Majoris	5.15
	37	37 Ursae Majoris	5.16
c	16	16 Ursae Majoris	5.18
	67	67 Ursae Majoris	5.22
	31	31 Ursae Majoris	5.27
	17	17 Ursae Majoris	5.28
	57	57 Ursae Majoris	5.30
	61	61 Ursae Majoris	5.31
	74	74 Ursae Majoris	5.37
	82	82 Ursae Majoris	5.46
A	2	2 Ursae Majoris	5.47
	70	70 Ursae Majoris	5.54
	59	59 Ursae Majoris	5.56
	6	6 Ursae Majoris	5.57
	42	42 Ursae Majoris	5.57
	81	81 Ursae Majoris	5.60
π¹	3	Pi-1 Ursae Majoris, Muscida	5.64	46.5	< post-classical Latin musus "snout", "muzzle" Muscida shared with ο Ursae Majoris BY Draconis type variable star
	43	43 Ursae Majoris	5.66
	73	73 Ursae Majoris	5.68
	84	84 Ursae Majoris	5.68
	86	86 Ursae Majoris	5.70
b	5	5 Ursae Majoris	5.72
	62	62 Ursae Majoris	5.73
	32	32 Ursae Majoris	5.74
	22	22 Ursae Majoris	5.77
	39	39 Ursae Majoris	5.79
	71	71 Ursae Majoris	5.82
	66	66 Ursae Majoris	5.83
	58	58 Ursae Majoris	5.94
	51	51 Ursae Majoris	6.01
	76	76 Ursae Majoris	6.02
	75	75 Ursae Majoris	6.07
	60	60 Ursae Majoris	6.09
	35	35 Ursae Majoris	6.32
	41	41 Ursae Majoris	6.34
	68	68 Ursae Majoris	6.34
		Groombridge 1830	6.42	29.9	nearby yellow subdwarf
	28	28 Ursae Majoris	6.51
	65	65 Ursae Majoris	6.54		binary star; component magnitudes: 6.54, 7.16
	71	71 Ursae Majoris	7.09
	40	40 Ursae Majoris	7.22
		Lalande 21185	7.48	8.2	nearby, has possible planets
		W Ursae Majoris	7.75v	162	variable star: 7.75–8.48
		Winnecke 4, M40	9.0	510	double star; component magnitudes: 9.0, 9.3
		SZ Ursae Majoris	9.31v		variable star
		CF Ursae Majoris	12.00v		variable star
		WX Ursae Majoris	14.4v		variable star