List of open clusters

The open cluster Messier 6 in the constellation Scorpius is also known as the Butterfly Cluster or NGC 6405

This is a list of open clusters located in the Milky Way. An open cluster is an association of up to a few thousand stars that all formed from the same giant molecular cloud. There are over 1,000 known open clusters in the Milky Way galaxy, but the actual total may be up to ten times higher. ^[1] The estimated half-lives of clusters, after which half the original cluster members will have been lost, range from 150 million to 800 million years, depending on the original density. ^[2]

Table

Milky Way

Known and candidate Milky Way open clusters

Cluster identifier	Image	Epoch J2000		Constellation	Distance (Light-years)	Age (Myr)	Diameter	Apparent magnitude	Notes
		R. A.	Dec.
Hyades		04h 26.9m	+15° 52′	Taurus	153	625	330'	0.5	[3]
Coma Star Cluster		12h 22.5m	+25° 51′	Coma Berenices	280	400–500	120'	1.8	[4]
Messier 45 (Pleiades)		03h 47.4m	+24° 07′	Taurus	444	125	120'	1.2	[5]
IC 2602 (Southern Pleiades/Theta Carinae Cluster)		10h 43.2m	−64° 24′	Carina	486	30	100'	1.9	[6]
Alpha Persei Cluster		03h 26.0m	+49° 07′	Perseus	570	50	300'	1.2	[7]
IC 2391 (Omicron Velorum Cluster)		08h 40.6m	−53° 02′	Vela	574	30	60'	2.5	[6]
NGC 2451 A		07h 45.4m	−37° 58′	Puppis	600	50	45'	2.8	[8] [9]
Messier 44 (Beehive Cluster)		08h 40.4m	+19° 41′	Cancer	610	830	70'	3.1	[10] [11]
Melotte 186		18h 01.1m	+02° 54′	Ophiuchus	652	100	240'	3.0	[12]
Blanco 1		00h 04.3m	−29° 56′	Sculptor	850+160 −130	100	90'	4.5	[6]
Messier 7 (Ptolemy's Cluster)		17h 53.8m	−34° 47′	Scorpius	980 ± 33	224	80'	3.3	[8] [13]
Messier 39 (Pyramid Cluster)		21h 31.8m	+48° 27′	Cygnus	1,010	280	30'	4.6	[1] [8]
IC 348		03h 44.6m	+32° 10′	Perseus	1,028	44	7'	7.3	[1]
NGC 6633		18h 27.7m	+06° 34′	Ophiuchus	1,040	660	20'	4.6	[14]
Pi Puppis Cluster		07h 08m	−37° 10′	Puppis	1,040.5		50'	2.1	[15]
NGC 2232		06h 26.4m	−04° 45′	Monoceros	1,060	53	45'	3.9	[1] [8]
Trumpler 10		08h 47.8m	−42° 29′	Vela	1,100	35	14'	4.6	[1] [8]
IC 4665 (Summer Beehive Cluster)		17h 46.3m	+05° 43′	Ophiuchus	1,120	43	70'	4.2	[1]
NGC 2547		08h 10.8m	−49° 18′	Vela	1,190	38	25'	4.7	[8]
Collinder 140		07h 24.5m	−31° 51′	Canis Major	1,226	35	42'	3.5	[1] [8]
IC 4756 (Graff's Cluster)		18h 39.0m	−05° 27′	Serpens	1,300	500	40'	4.6	[1] [8]
NGC 2516 (Southern Beehive Cluster)		07h 58.0m	−60° 48′	Carina	1,300	141	30'	3.8	[8] [13]
Lambda Orionis Cluster		05h 35m	+09° 56′	Orion	1,300	5		2.8	[16]
NGC 3532 (Wishing Well Cluster)		11h 06.4m	−58° 40′	Carina	1,321	316	50'	3.0	[8] [13]
Trapezium Cluster		5h 35.4m	−05° 27′	Orion	1,344 ± 20	0.3	0.783'	4.0	[17]
NGC 752		01h 57.7m	+37° 47′	Andromeda	1,470	1,700–2,000	75'	5.7	[18]
Messier 34 (Spiral Cluster)		02h 42.1m	+42° 46′	Perseus	1,500	180	36'	5.2	[1] [13]
Messier 6 (Butterfly Cluster)		17h 40.1m	−32° 13′	Scorpius	1,590	94	20'	4.2	[1]
Messier 47		07h 36.6m	−14° 30′	Puppis	1,600	73	25'	4.4	[1]
NGC 6281 (Moth Wing Cluster)		17h 04.7m	−37° 59′	Scorpius	1,611	220	8'	5.4	[1]
NGC 1980 (The Lost Jewel of Orion)		5h 25.43m	−05° 54′	Orion	1,793	4.7	14'	2.5	[19]
Messier 25		18h 31.7m	−19° 07′	Sagittarius	2,000	92	30'	4.6	[1]
Messier 23		17h 57.0m	−18° 59′	Sagittarius	2,050	300	30'	5.5	[1] [13]
NGC 5662		14h 35.6m	−56° 37′	Centaurus	2,170	70	30'	5.5	[1] [13]
NGC 225		00h 43.6m	+61° 46′	Cassiopeia	2,200	130	12'	7.0	[1]
NGC 5460		14h 07.4m	−48° 20′	Centaurus	2,350	160	36'	5.6	[1] [13]
NGC 2264		06h 41.0m	+09° 53′	Monoceros	2,350 ± 52	1.5	40'	3.9	[20]
Messier 41		06h 46.0m	−20° 46′	Canis Major	2,360	240	40'	4.5	[1] [13]
NGC 6025		16h 03.3m	−60° 26′	Triangulum Australe	2,410	130	14'	5.1	[1] [13]
Messier 48		08h 13.7m	−05° 45′	Hydra	2,500	400	30'	5.8	[1]
IC 5146		21h 53.5m	+47° 16′	Cygnus	2,500±100	1	9'	7.2	[1]
Messier 67 (King Cobra Cluster/Golden Eye Cluster)		08h 51.3m	+11° 48′	Cancer	2,610 – 2,930	4,000	25'	6.9	[1] [13]
NGC 2301		06h 51.75m	+00° 28′	Monoceros	2,840	165	12'	6.0	[21]
Messier 50 (Heart-shaped Cluster)		07h 02.6m	−08° 23′	Monoceros	2,870	130	14'	5.9	[22]
IC 4651		17h 24.8m	−49° 56′	Ara	2,900	1,900	10'	6.9	[1] [13]
NGC 7822 (Berkeley 59)		00h 04.0m	+68° 35′	Cepheus	2,900	2	180'		[23]
Messier 35 (Shoe-Buckle Cluster)		06h 09.1m	+24° 21′	Gemini	2,970	180	25'	5.0	[22]
NGC 3114		10h 02.7m	−60° 07′	Carina	2,970	124	36'	4.2	[1]
NGC 381		01h 08.3m	+61° 35′	Cassiopeia	3,120 ± 300	320	7'	9.3	[1]
Messier 93 (Critter Cluster)		07h 44.6m	−23° 52′	Puppis	3,380	390	10'	6.2	[1]
NGC 1502 (Golden Harp Cluster)		04h 07.8m	+62° 20′	Camelopardalis	3,452	10	8'	5.7	[1]
Messier 38 (Starfish Cluster)		05h 28.7m	+35° 51′	Auriga	3,480	316	20'	6.4	[1]
NGC 6087 (S Normae Cluster)		16h 18.8m	−57° 56′	Norma	3,500	70	14'	5.4	[1] [13]
NGC 6204		16h 46.1m	−47° 01′	Ara	3,540	79	6'	8.2	[1]
Collinder 121		07h 08m	−37° 10′	Canis Major	3,590 ± 0.72		50'	2.6	[24]
NGC 2169		06h 08.4m	+13° 58′	Orion	3,600	12	5'	5.9	[1]
NGC 2360 (Caroline's Cluster)		07h 17.7m	−15° 38′	Canis Major	3,700	1,000	13'	7.2	[1] [13]
Messier 21 (Webb's Cross)		18h 04.2m	−22° 29′	Sagittarius	3,930	12	14'	5.9	[1]
NGC 189		00h 39.7m	+61° 04′	Cassiopeia	4,200	10	3.7'	8.8	[1]
Messier 18 (Black Swan Cluster)		18h 20.0m	−17° 06′	Sagittarius	4,230	17	5'	6.9	[1]
Messier 36 (Pinwheel Cluster)		05h 36.2m	+34° 08′	Auriga	4,340 ± 0.87	25	10'	6.0	[1]
NGC 6242		16h 55.6m	−39° 28′	Scorpius	4,350 ± 0.53	50	9'	6.4	[1] [13]
Messier 37 (Salt and Pepper Cluster)		05h 52.3m	+32° 33′	Auriga	4,500	347	14'	5.6	[1]
Messier 52 (Scorpion Cluster)		23h 24.8m	+61° 35′	Cassiopeia	4,600	160	15'	6.9	[1]
NGC 6067		16h 13.2m	−54° 13′	Norma	4,621	170	14'	5.6	[1] [13]
NGC 2362 (Tau Canis Majoris Cluster)		07h 18.6m	−24° 59′	Canis Major	4,830 ± 0.97	4–5	5'	4.1	[25]
Messier 46		07h 41.7m	−14° 49′	Puppis	4,920 ± 980	250	20'	6.1	[1]
Messier 26		18h 45.3m	−09° 23′	Scutum	5,160	85	7'	8.0	[1]
NGC 2244 (Satellite Cluster)		06h 31.9m	+04° 56′	Monoceros	5,200	1.9	30'	4.8	[1]
NGC 2355		07h 17.0m	+13° 47′	Gemini	5,380	955	5'	9.7	[1] [13]
NGC 188 (Polarissima Cluster)		00h 48.4m	+85° 15′	Cepheus	5,400	6,600	17'	8.1	[13] [26]
NGC 129		00h 30.0m	+60° 13′	Cassiopeia	5,450	76	21′	6.5	[27]
NGC 3766 (Pearl Cluster)		11h 36.2m	−61° 37′	Centaurus	5,500	14	12'	5.3
NGC 6231 (Baby Scorpion Cluster)		16h 54.1m	−41° 50′	Scorpius	5,600 ± 400	6	14'	2.6	[1] [13]
Messier 16 (Eagle Nebula)		18h 18.8m	−13° 49′	Serpens	5,700 ± 400	1.3	6'	6.0	[1]
Messier 11 (Wild Duck Cluster)		18h 51.1m	−06° 16′	Scutum	6,120	250	13'	5.8	[1] [13] [28]
NGC 2175		06h 09.7m	+20° 29′	Orion	6,350	8.9	5'	6.8	[1]
NGC 6756		19h 08.7m	+04° 42′	Aquila	6,363	62	4'	4.5	[1]
NGC 4755 (Jewel Box)		12h 53.6m	−60° 22′	Crux	6,500	14	10'	4.2	[1] [13]
NGC 6200		16h 44.1m	−47° 28′	Ara	6,700	8.5	12'	7.4	[29]
NGC 6031		16h 07.9m	−54° 03′	Norma	6,800 ± 2.3	117	3'	8.5	[1] [30]
NGC 663		01h 46.1m	+61° 14′	Cassiopeia	6,850	25	14'	7.1	[1]
NGC 637		01h 43.0m	+64° 02′	Cassiopeia	7,045 ± 1.409	10	4.2'	8.2	[1]
NGC 2129		06h 01.1m	+23° 19′	Gemini	7,200	10	5'	6.7	[1] [31]
NGC 869 (h Persei)		02h 19.1m	+57° 09′	Perseus	7,460	12	18'	3.7	[1]
NGC 1931		05h 31.0m	+34° 15′	Auriga	7,500	10	3'	10.1	[1]
NGC 884 (χ Persei)		02h 22.0m	+57° 08′	Perseus	7,600	14	18'	3.8	[1] [13]
NGC 7789 (White Rose Cluster)		23h 57.4m	+56° 43′	Cassiopeia	7,600	1,700	16'	6.7	[32]
NGC 457 (Dragonfly Cluster)		01h 19.1m	+58° 17′	Cassiopeia	7,922	21	20'	6.4	[33]
Collinder 261		12h 38.0m	−68° 22′	Musca	8,150	8,000	9'	10.7	[34] [35]
NGC 659 (Yin-Yang Cluster)		01h 44.4m	+60° 40′	Cassiopeia	8,200	35	5'	7.9	[1]
NGC 3293		10h 35.8m	−58° 13′	Carina	8,400	8	8'	4.7
NGC 7419		22h 54.3m	+60° 48.9′	Cepheus	9,130		2'	13
Messier 103		01h 33.4m	+60° 39′	Cassiopeia	9,400	16	5'	7.4	[36]
NGC 2509		08h 00.7m	−19° 04′	Puppis	9,500	Uncertain [37]	10'	9.3	[38]
Messier 24 (Small Sagittarius Star Cloud)		18h 17.0m	−18° 29′	Sagittarius	10,000	220	90'	2.5	[1] [13]
NGC 6834		19h 52.2m	+29° 25′	Cygnus	10,850	76	5'	7.8	[1] [30]
NGC 2158		06h 07.4m	+24° 06′	Gemini	11,000	1,054	5'	8.6	[1]
NGC 2439		07h 40.8m	−31° 41′	Puppis	12,570	25	9'	6.9	[1] [13]
NGC 6791		19h 20.9m	+37° 46′	Lyra	13,300	8,900	16'	9.5	[1] [13]
NGC 2204		06h 15.5m	−18° 40′	Canis Major	13,400 ± 1.3	787	13'	8.6	[1]
Gaia 1		06h 45.9m	−16° 45′	Canis Major	15,000	6,300	13'	8.3
Teutsch 2		05h 41.4m	+39° 14′	Auriga	18,590	900	2'	11	[39]
Alicante 7 (RSGC5)		18h 44m 29.45s	−03° 30′ 02.4″	Scutum	19,600	16–20
Alicante 10 (RSGC6)		18h 45m 30s	−03° 40′ 00″	Scutum	19,600	16–20
Arches Cluster		17h 45m 50.5s	−28° 49′ 28″	Sagittarius	25,000	2,500,000
Arp-Madore 2		07h 38.8m	−33° 51′	Puppis	30,000	5,000	1.3'		[40]
Ru 7		06h 58.9m	−13° 15′	Canis Major					[ citation needed ]

Local Group

Open clusters of the Local Group ^[41]

Identifier	Image	Epoch J2000		Diameter (′)	Apparent Magnitude	Galaxy
		Right ascension	Declination
NGC 2070		05h 38.7m	−69° 06′	3.5'	7.25	LMC [42] [43]
Hodge 301		05h 38.5m	−69° 04′	0.5'	11	LMC [44] [45]

See also

• Lists of astronomical objects
• List of globular clusters
• Lists of clusters

References

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