R136 | |
---|---|
Observation data (J2000.0 epoch) | |
Right ascension | 05h 38m 42.396s [1] |
Declination | −69° 06′ 03.36″ [1] |
Distance | 157 kly (48.5 kpc) |
Apparent magnitude (V) | 9.50 |
Physical characteristics | |
Mass | 90,000 [2] M☉ |
Estimated age | 1.5+0.3 −0.7 million years [2] |
Other designations | UCAC2 1803442, SAO 249329, HD 38268, TYC 9163-1014-1, CD-69 324, GC 7114 [3] |
Associations | |
Constellation | Dorado |
R136 (formerly known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue [4] ) is the central concentration of stars in the NGC 2070 star cluster, which lies at the centre of the Tarantula Nebula in the Large Magellanic Cloud. When originally named it was an unresolved stellar object (catalogued as HD 38268 and Wolf-Rayet star Brey 82) but is now known to include 72 class O and Wolf–Rayet stars within 5 parsecs (20 arc seconds) of the centre of the cluster. [5] The extreme number and concentration of young massive stars in this part of the LMC qualifies it as a starburst region. [6]
R136 produces most of the energy that makes the Tarantula Nebula visible. The estimated mass of the cluster is 450,000 solar masses, suggesting it may become a globular cluster in the future. [7] R136 has around 200 times the stellar density of a typical OB association such as Cygnus OB2. [8] The central R136 concentration of the cluster is about 2 parsecs across, although the whole NGC 2070 cluster is much larger. [8]
R136 is thought to be less than 2 million years old. [8] [9] None of the member stars are significantly evolved, and none are thought to have exploded as supernova. Because of this, the cluster contains no red supergiants, blue hypergiants, or luminous blue variables. The brightest stars are WNh, O supergiants, and OIf/WN slash stars, all extremely massive fully convective stars. A small number of B-type main sequence stars have been detected in the outskirts of the cluster, but less massive and less luminous stars cannot be resolved from the dense cluster core at the large distance of the LMC. [5]
R136a is the bright knot at the centre of R136. It consists of eight extremely massive stars, three of them Wolf-Rayet stars and the rest early O-class stars. [2]
The cluster contains many of the most massive and luminous stars known, including R136a1. Within the central 5 parsecs there are 32 of the hottest type O stars (O2.0–3.5), 40 other O stars, and 12 Wolf-Rayet stars, mostly of the extremely luminous WNh type. Within 150 parsecs there are a further 325 O stars and 19Wolf-Rayet stars. [5] Several runaway stars have been associated with R136, including VFTS 682. [10] R136 was first resolved into three components R136a, R136b, and R136c. R136a was resolved using speckle interferometry and eventually space-based observations into as many as 24 components, [11] dominated by R136a1, R136a2, and R136a3, all three being extremely massive WNh stars several million times more luminous than the sun. [12]
Name | Right ascension [5] | Declination [5] | V [2] (F555W) | Spectral type [12] | MV [13] (F555W) | Temperature (K) [12] [14] | Luminosity (L☉) [12] [14] | Mass (M☉) [12] [14] |
---|---|---|---|---|---|---|---|---|
R136a1 | 05h 38m 42.39s | −69° 06′ 02.91″ | 12.28 | WN5h | −8.18 | 46,000 | 4,677,000 | 196 |
R136a2 | 05h 38m 42.40s | −69° 06′ 02.88″ | 12.80 | WN5h | −7.80 | 50,000 | 3,548,000 | 151 |
R136a3 | 05h 38m 42.33s | −69° 06′ 03.27″ | 12.97 | WN5h | −7.52 | 50,000 | 3,631,000 | 155 |
R136a4 | 05h 38m 42.34s | −69° 06′ 02.60″ | 13.96 | O3 V((f*))(n) | −6.68 | 50,000 | 1,905,000 | 108 |
R136a5 | 05h 38m 42.43s | −69° 06′ 02.73″ | 13.71 | O2I(n)f* | −6.86 | 48,000 | 2,089,000 | 116 |
R136a6 | 05h 38m 42.29s | −69° 06′ 03.37″ | 13.35 | O2I(n)f*p | −6.46 | 52,000 | 1,738,000 | 105 |
R136a7 | 05h 38m 42.41s | −69° 06′ 02.57″ | 13.97 | O3III(f*) | −6.59 | 54,000 | 2,291,000 | 127 |
R136a8 | 05h 38m 42.37s | −69° 06′ 01.9″? | 14.42 | O2–3V [2] | −6.05 [2] | 49,500 | 1,479,000 | 96 |
R136b | 05h 38m 42.74s | −69° 06′ 03.78″ | 13.24 | O4If | −7.70 | 35,500 | 2,239,000 | 92 |
R136c | 05h 38m 42.90s | −69° 06′ 04.83″ | 12.86 | WN5h [15] | −7.9 [5] | 42,170 [15] | 3,802,000 [15] | 142 [15] |
NGC 3603 is a nebula situated in the Carina–Sagittarius Arm of the Milky Way around 20,000 light-years away from the Solar System. It is a massive H II region containing a very compact open cluster HD 97950.
The Arches Cluster is the densest known star cluster in the Milky Way, about 100 light-years from its center in the constellation Sagittarius, 25,000 light-years from Earth. Its discovery was reported by Nagata et al. in 1995, and independently by Cotera et al. in 1996. Due to extremely heavy optical extinction by dust in this region, the cluster is obscured in the visual bands, and is observed in the X-ray, infrared and radio bands. It contains approximately 135 young, very hot stars that are many times larger and more massive than the Sun, plus many thousands of less massive stars.
NGC 2060 is a star cluster within the Tarantula Nebula in the Large Magellanic Cloud, very close to the larger NGC 2070 cluster containing R136. It was discovered by John Herschel in 1836. It is a loose cluster approximately 10 million years old, within one of the Tarantula Nebula's superbubbles formed by the combined stellar winds of the cluster or by old supernovae.
R136b is a blue supergiant star in the R136 cluster in the Large Magellanic Cloud. It is one of the most massive and most luminous stars known. It is found in the dense R136 open cluster at the centre of NGC 2070 in the Tarantula Nebula.
R136a1 is one of the most massive and luminous stars known, at nearly 200 M☉ and nearly 4.7 million L☉, and is also one of the hottest, at around 46,000 K. It is a Wolf–Rayet star at the center of R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula Nebula in the Large Magellanic Cloud. The cluster can be seen in the far southern celestial hemisphere with binoculars or a small telescope, at magnitude 7.25. R136a1 itself is 100 times fainter than the cluster and can only be resolved using speckle interferometry.
Melnick 42 is a massive blue supergiant star in the Tarantula Nebula in the Large Magellanic Cloud located in the constellation Dorado. Although it is only 21 times the size of the sun, its high temperature of 47,300 K makes it one of the most luminous stars of the Tarantula Nebula at 3,600,000 L☉. It is less than two parsecs from the centre of the R136 cluster, although that is well outside the central core.
VFTS 682 is a Wolf–Rayet star in the Large Magellanic Cloud. It is located over 29 parsecs (95 ly) north-east of the massive cluster R136 in the Tarantula Nebula. It is 138 times the mass of the Sun and 3.2 million times more luminous, which makes it one of the most massive and most luminous stars known.
R136a2 is a Wolf-Rayet star residing near the center of the R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula Nebula, a massive H II region in the Large Magellanic Cloud which is a nearby satellite galaxy of the Milky Way. It has one of the highest confirmed masses and luminosities of any known star, at about 151 M☉ and 3.5 million L☉ respectively.
R136c is a star located in R136, a tight knot of stars at the centre of NGC 2070, an open cluster weighing 450,000 solar masses and containing 10,000 stars. At 142 M☉ and 3.8 million L☉, it is the one of the most massive stars known and one of the most luminous, along with being one of the hottest, at over 40,000 K. It was first resolved and named by Feitzinger in 1980, along with R136a and R136b.
HD 38282 is a massive spectroscopic binary star in the Tarantula Nebula, consisting of two hydrogen-rich Wolf-Rayet stars.
R136a3 is a Wolf–Rayet star in R136, a massive star cluster located in Dorado. It is located near R136a1, the most massive and luminous star known. R136a3 is itself one of the most massive and most luminous stars known at about 179 times more massive and 5 million times more luminous than the Sun.
BI 253 is an O2V star in the Large Magellanic Cloud and is a primary standard of the O2 type. It is one of the hottest main-sequence stars known and one of the most-massive and most-luminous stars known.
Melnick 34, also called BAT99-116, is a binary Wolf–Rayet star near R136 in the 30 Doradus complex in the Large Magellanic Cloud. Both components are amongst the most massive and most luminous stars known, and the system is the most massive known binary system.
BAT99-98 is a Wolf–Rayet star located in the Large Magellanic Cloud, in NGC 2070 near the R136 cluster in the Tarantula Nebula. At 226 M☉ and 5,000,000 L☉ it is one of the most massive and luminous stars currently known.
VFTS 352 is a contact binary star system 160,000 light-years (49,000 pc) away in the Tarantula Nebula, which is part of the Large Magellanic Cloud. It is the most massive and earliest spectral type overcontact system known.
LH 41-1042 is a Wolf–Rayet star located in the Large Magellanic Cloud (LMC). It is an extremely rare member of the WO oxygen sequence, the second to be discovered in the LMC and one of only three found so far in that galaxy.
R145 is a spectroscopic binary star in the Tarantula Nebula in the Large Magellanic Cloud located in the constellation Dorado. Both components are amongst the most luminous known.
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