List of O-type stars

Last updated July 28, 2025

This is a list of O-type stars by their distance from Earth.^[1]^[2]^[3]

List

Milky Way galaxy

Star system ← ←	Median distance (ly)	Stars in system	Spectral type	Apparent magnitude (V)	Comments and references
Zeta Ophiuchi	440 ± 40	1	O9.5 V	2.56 – 2.58	The closest O-type star to Earth.
Phi Persei B	720 ± 30	1	sdO	4.06	Has a B-type companion star.
28 Cygni B	840 ± 20	2	sdO	4.93	Has a B-type companion star.
Iota Arae B	920 ± 20	2	sdO	5.18–5.26	Has a B-type companion star.
Rho¹ Arae B	990 ± 10	2	sdO	6.275	Has a B-type companion star.
Kappa¹ Apodis B	1,060 ± 20	1	sdO	5.52	Has a B-type companion star.
Zeta Puppis (Naos)	1,080 ± 40	1	O4If(n)p	2.24 - 2.26
Gamma² Velorum B (Suhail al Muhlif/Regor)	1096+26 −23	2	O7.5III	1.83	Has a Wolf-Rayet companion star.
Theta² Orionis A	1,100 ± 80	3	O9.5IVp	5.02
Mintaka A (Delta Orionis, 34 Orionis)	1,200	3	O9.5II	2.5
V2119 Cygni	1203±22.3	1	sdO
60 Cygni	1225±57	1	sdO
Upsilon Orionis	1,260±75	1	B0V or O9.7V	+4.618±0.013
Alnitak (Zeta Orionis, 50 Orionis)	1,260 ± 180	3	O9.5Iab	1.77
Sigma Orionis A	1263±4.3	2	O9.5V	4.07
Meissa A (Lambda Orionis)	1260±200	1	O8 III((f))	3.7
AE Aurigae	1,320 ± 40	1	O9.5V	5.96
Xi Persei (Menkib)	1,340±65	1	O7.5III(n)((f))	4.04
Theta¹ Orionis C1	1340±65	1	O6Vp	5.13
Iota Orionis (Haytsa)	1343+45.6 −42.3	3	O9 III	2.77
LS Muscae	1383±43	1	sdO
W40 IRS 1A South	1,420	1	O9.5	15	Member of Westerhout 40.
IN Comae Berenices (HD 112313)	1,650 ± 40	2	G5 III + sdO	8.69	Central star of LoTr 5 Planetary Nebula. Has a G-type companion star.
HD 49798	1,699 ± 46	1	sdO6p
10 Lacertae	1,800±103	1	O9V	4.880
FY Canis Majoris	1,820 ± 70	2	B0.5 IVe + sdO	4.8 - 6.25	Has a B-type companion star.
Mu Columbae	1,894±111	1	O9.5 V	5.18
HD 186924	2000	1	O6fp		It is the central star of NGC 6826 Planetary Nebula.
HD 206267	2,000	2	O6V((f)) + O9V	5.70
HD 49798	2120.02	1	sdO6p	8.287
UY Sextantis	2,200 ± 100	1	sdO9VII:He6	13.49
68 Cygni	2,200 ± 200	1	O7.5IIIn((f))	5.00
Delta Circini	2,300 ± 200	1	O7.5III(f) (O8IV + O9.5V + B0.5V)	5.09
S Monocerotis (15 Monocerotis)	2,300 ± 200	3	O7V((f))zvar[4] + O9.5Vn
HD 73882	2,400 ± 100	1	O8.5IV	7.19 - 7.29
1 Camelopardalis	2,580 ± 100	1	O9.7IIn	5.77
X Persei	2,600 ± 100	1	O9.5IIIe-B0Ve	6.778
NSVS 14256825	2,700 ± 100	2	sdOB / M V	13.2	Has a M-type companion star.
Lambda Cephei	3,098.5	1	O6.5If(n)p	+5.050
HD 193322A	3,100	2	O9Vnn + O8.5 III	+5.958
Mu Normae	3,260	1	O9.7Iab	4.91
HD 35914	3,600	1	O7fp		It is the central star of IC 418 Planetary Nebula.
63 Ophiuchi	3,600 ± 300	1	O8II((f))	6.20
UW Canis Majoris	3,800	2	O7.5-8Iabf + O9.7Ib	4.95
Trumpler 27-27	3,900	1	O8III((f))
V3903 Sagittarii (11 Sagittarii)	3,900 ± 100	1	O7V(n)z + B0:V:	7.00–7.45	Has a B-type companion.
HD 148937	3,900 ± 100	1	O6f?p	6.73
19 Cephei	3,913.88	1	O9Ib	5.08
HD 54879	4100 ± 200	1	O9.7V	7.65
HD 164492 A	4100 ± 200	1	O7.5III		Part of Trifid Nebula
9 Sagittarii	4,100 ± 400	1	O4V((f))z	5.97
15 Sagittarii	4,200±650	1	O9.7 Iab	5.37
AO Cassiopeiae (Pearce's Star)	4,300 ± 300	2	O8V((f)) + O9.2II	6.07-6.24
HD 149404 (V918 Scorpii)	4,300 ± 400	2	O7.5I(f) + ON9.7I	5.42 - 5.50
HD 150136	4,310 ± 390	3	O3 V((f*)) - O3.5 V((f+)) + O5.5-6 V((f)) + O6.5-7 V((f))	5.54
16 Sagittarii	4,600	1	O9.5 III	6.02
BE Ursae Majoris	4,600 ± 200	2	DO + M1e–M5e	14.8 to 17.8	Has a M-type companion star.
Y Cygni	4,900	2	O9.5V + O9.5V	7.3 - 7.9
WR 140 (SBC9 1232)	4950 ± 21	2	WC7pd + O5.5fc	6.85	Has a Wolf-Rayet Companion.
HD 92206 C	5,000	3	O8V + O9.7V + B2:	8.966	Has a B-type companion.
HD 229196	5,000	1	O5
HD 93521	5,000 ± 300	1	O9.5IIInn or O9.5Vp	7.03
Tau Canis Majoris	5,120.66	3	O9II	4.40
HD 46223	5,200	1	O4V
HD 46150	5,200	1	O5V
4U 1700-37 (V884 Scorpii)	5,200 ± 200	1	O6Iafcp	6.51
Plaskett's Star (V640 Monocerotis)	5,245	2	O8I + O7.5III	6.06
Cygnus OB2-8A	5,400 ± 200	1	O6If + O5.5III(f)	9.06
BD+43 3654	5,400 ± 300	1	O4If	10.06
HD 15558 (HIP 11832)	5,700	1	O4.5III(f) (O5.5III(f) + O7V)	7.87
HD 168076	5,700±400	2	O3.5V + O7.5V	+8.24
NGC 7662	5,730 ± 340	1	sdO		Central star of NGC 7662 Planetary Nebula.
Prisms 24-17	5,900	1	O3.5III
HD 48099	5,965	2	O5.5V((f)) + O9V	6.37
HD 165319	6,000	1	O9.7Ib		Central star of Sh2-46 Nebula.
Alpha Camelopardalis	6,000	1	O9Ia	4.29
WR 133 (V1676 Cyg)	6,100 ± 300	2	O9I	6.75 - 6.84	Has a Wolf-Rayet Companion.
HD 191612	6,100 ± 300	1	O6.5f?pe–O8fp (O8fp + B1V)	7.84 – 7.91
HD 108	6,230 ± 360	1	O4–8f?p	7.40
HD 59088	6,500	1	O(H)6f		It is the central star of NGC 2392 Planetary Nebula.
WR 25 (HD 93162)	6,500	2	O2.5If*/WN6 + OB	8.80
Pismis 24-1 (HD 319718)	6,500	2	O3.5If*+O4III(f+)
WR 137	6,700 ± 200	1	WC7pd + O9V	7.91	Has a Wolf-Rayet Companion.
CV Serpentis	6,700 ± 200	2	WC8d + O8-9IV	9.08	Has a Wolf-Rayet Companion.
LY Aurigae	6,800	3	O9II + O9III + B0.5III	6.85 (6.66 - 7.35)	Has B-type companion.
HD 151804 (V973 Scorpii)	7,000	1	O8 Iaf	5.22 - 5.28
HD 138403	7175.44	1	O8(f)ep		It is the central star of Hen 2-131 Planetary Nebula.
Cygnus X-1 (HDE 226868)	7,300 ± 200	2	O9.7Iab	8.95	Has a Black Hole Companion.
Theta Muscae	7,400	4	O6/7V + O9.5/B0Iab+O9III	5.53	Has a Wolf-Rayet Companion.
HD 92206 B	7,400 ± 300	1	O6.5V[8] or O6V((f))z
PSR B1259−63/LS 2883	7,500	2	O9.5Ve + PSR	10.34	Has a Pulsar Companion.
Eta Carinae (Eta Argus)	7,500	2	O	−1.0 to ~7.6	part of Trumpler 16 in the Carina Nebula.
HD 93129	7,500	2	O2If* (O2If+O3.5V) + O3.5 V((f))z	6.90	Part of Trumpler 14.
QZ Carinae (HD 93206)	7,501.6	4	O9.7I+O8III+O9V	6.24
HD 93205 (V560 Carinae)	7,600 ± 400	2	O3.5Vf + O8V	7.75
HD 97319	7,800-9,800	1	O		Part of NGC 3576.
HD 97484	7,800-9,800	1	O		Part of NGC 3576.
HD 93250	7,900 ± 400	1	O4 IV(fc)	7.41
6 Cassiopeiae	8,000	2	A2.5 Ia+ + O9.75	5.34 - 5.45	Has a A-type Hypergiant Companion.
HD 93160	8,000	1	O6III
LS 5039	8200±300	1	O(f)N6.5V + BH	11.27	Has a Black Hole Companion.
WR 22	8,300 ± 700	2	WN7h + O9III-V	6.42	Has a Wolf-Rayet Companion.
HD 92206 A	8,400 ± 500	2	O6.5V + O6.5V, O6V((f))z (combined)	+8.219
Abell 63	8,810	1	sdO		Center Star of Abell 63 Planetary Nebula.
HD 303308	9,200	1	O3V
LSS 4067 (CD−38°11748)	9,500–12,700	1	O4.5Ifpe	11.44
DH Cephei	9,600 ± 400	2	O5.5 V + O6 V	8.61
BD+60°2522	9,800 ± 400	1	O6.5(f)(n)p	8.67
HD 93130	10,000	1	O7II(f)
HD 93403	10,000	1	O5.5III(fc)var	7.272
HD 93632	10,000	1	O5III(f)
LSS 4067	11,000	1	O4.5Ifpe		Part of HM 1.
HM 1-6	11,000	1	O5If		Part of HM 1.
HM 1-8	11,000	2	O4.5IV(f) + O9.7V		Part of HM 1.
HD 35619	12,000	1	O7.5V((f))z	8.572
WR 9	12,000 ± 600	2	WC4 + O7	10.50	Has a Wolf-Rayet Companion star.
MY Camelopardalis	13,050	1	O6nn (O6V((f)) + O6V((f)))	9.80 - 10.15
WR 21a	13,100 ± 700	1	O3/WN5ha + O3Vz((f*))	12.661	Has a Wolf-Rayet Companion.
CD Crucis (WR 47)	14,000	2	WN6o + O5V	10.81	Has a Wolf-Rayet Companion.
WR 20a	14,000 ± 1,000	2	O3If/WN6 + O3If/WN6	13.28
HD 64568	15,000 ± 1,000	1	O3V((f*))z	9.39
TU Muscae	15500	2	O7V + O8V	8.307
NGC 1624-2	16,800	1	O7f?cp	11.57
GCIRS 16SW	20,000	1	Ofpe/WN9
GCIRS 8*	20,000	1	O5
V1936 Aquilae	20,000	1	O4I	15.1
Westerhout 51d	20,000	1	O		Member of Westerhout 51.
Westerhout 51-3	20,000	1	O3-8V		Member of Westerhout 51.
Westerhout 51-57	20,000	1	O4V		Member of Westerhout 51.
MSP 183	20,000	1	O3V(f)		Part of Westerlund 2.
HD 116852 (HIP 65890)	20,580	1	O8.5 II-III ((f))	8.47
WR 30a	21,920+1,400 −1,090	2	WO4 + O5((f))	12.73	Has a Wolf-Rayet Companion.
Centaurus X-3 (Krzemiński's star)	24,000 ± 2,000	2	O6-7 II-III + ?	13.25 (- 13.39) - 13.46
HD 15558 A	24,400	1	O5.5III(f)		Part of IC 1805.
MTT 68	24,787.88	1	O2If*	14.72
HD 97950 A3	24,800	1	O3III
WR 42e (2MASS J11144550-115001)	25,000	1	O3If*/WN6	14.53
HD 97950	25,000	1	O
Arches-F15	25,000	1	O6-7 Ia+
Arches-F18	25,000	1	O4-5 Ia+
WR 102ka (Peony star)	26,000	2	Ofpe/WN9
WR 148	27,000	2	WN8h + O5V?	10.3	Has a Wolf-Rayet Companion.
Westerhout 49-2	36,200	1	O2-3.5If*
Westerhout 49-3	36,200	1	O3-O7V
Mercer 30-1 A	40,000	1	O6-7.5lf+
US 708	60,300 ± 8,500	1	sdOHe	18.8

Magellanic Clouds

The Large Magellanic Cloud (LMC) is around 163 kly distant and the Small Magellanic Cloud (SMC) is around 204 kly distant

Host galaxy	Star system	Median distance (ly)	Stars in system	Spectral type	Apparent magnitude (V)	Comments and references
LMC	R126a4	157,000	1	03V((f*))(n)
LMC	R136a5	157,000	1	02l(n)f*
LMC	R136a6	157,000	1	02I(n)f*p
LMC	R136a8	157,000	1	02-3V
LMC	LH 10-3209 A	160,000	1	O3III(f*)		Part of NGC 1763.
LMC	Melenick 39 A	160,000	1	02.5If/WN6
LMC	Sk -65° 47	160,000	1	O4If
LMC	Sk -68° 137	160,000	1	OB
LMC	Sk -69° 212	160,000	1	06lf
LMC	Sk -69° 249 A	160,000	2	07lf
LMC	ST5-31	160,000	1	02-3(n)fp
LMC	TIC 276934932	160,000	2	O3If + O6V
LMC	R136a7	163,000	1	03III(f*)
LMC	MACHO 80.7443.1718	163,000	2	B0 Iae + O9.5 V	13.628	Has a B-type companion.
LMC	R136b	163,000	1	O4If	13.24
LMC	LH 54-425	163,000	2	O3V + O5V	13.13
LMC	HD 269810	163,000	1	O2III(f*)	12.22
LMC	HSH95-36	163,000	1	02 lf*
LMC	Melnick 42	163,000	1	O2If*	12.78	Part of Tarantula Nebula.
LMC	BI 253	164,000	1	O2V-III(n)((f*))	13.76
LMC	VFTS 243 (2MASS J05380840-6909190)	164,000	1	O7V(n)((f))	15.26	Has a Known Black Hole Companion
LMC	VFTS 102	164,000	1	O9:Vnnne	15.806
LMC	VFTS 352	164,000	2	O4.5 V(n)((fc)):z: + O5.5 V(n)((fc)):z:	14.38
LMC	VFTS 506	164,000	1	0N2V((n))((f*))
LMC	VFTS 621	164,000	1	02V((f*))z
LMC	VFTS 1021	164,000	1	04 lf+
LMC	LMC X-1	180,000	2	O8 IIIf or O8 f?p + BH	14.612 ± 0.171	Has a Black hole Companion.
SMC	SMC AB7	197,000	2	O6I(f)	13.016
SMC	SMC AB8	197,000	2	O4V	12.83
SMC	HD 5980	200,000	3	LBV + WN4 + OI	8.8 - 11.9
SMC	HD 346-W1	200,000	1	O5.5lf
SMC	HD 346-W3	200,000	1	O3V

Andromeda Galaxy and Triangulum Galaxy

The Andromeda Galaxy (M31) is 2.5 Mly distant and the Triangulum Galaxy is around 3.2 Mly distant

Host galaxy	Star system	Median distance (ly)	Stars in system	Spectral type	Apparent magnitude (V)
Andromeda	LGGS J004246.86+413336.4	2,500,000	1	O3-O5If
Triangulum	[BMS2003] 867	2,700,000	2	O4Iab+O4Ia
Triangulum	M33 X-7	2,700, 000±70000	2	O7-8III / BH	+18.70
Triangulum	M33-013406.63 (B416/UIT301)	3,000,000	1	O9.5Ia

Other Galaxies

Host Galaxy	Star system	Median distance (ly)	Stars in system	Spectral type	Apparent magnitude (V)	Comments and references
IC 3418	SDSS J1229+1122	550,000,000	1	O	22.85

References

↑ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR .
↑ Barry, Don C. (January 1970), "Spectral Classification of a and F Stars", Astrophysical Journal Supplement, 19: 281, Bibcode:1970ApJS...19..281B, doi:10.1086/190209.
↑ Frost, E. B. (December 1924), "Fourteen spectroscopic binaries", Astrophysical Journal, 60: 319–320, Bibcode:1924ApJ....60..319F, doi:10.1086/142868.

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[GaiaDR2-1] Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR .

[Barry1970-2] Barry, Don C. (January 1970), "Spectral Classification of a and F Stars", Astrophysical Journal Supplement, 19: 281, Bibcode:1970ApJS...19..281B, doi:10.1086/190209.

[Frost1924-3] Frost, E. B. (December 1924), "Fourteen spectroscopic binaries", Astrophysical Journal, 60: 319–320, Bibcode:1924ApJ....60..319F, doi:10.1086/142868.

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