R136a1 Star

RMC 136a1 (usually abbreviated to R136a1) is one of the most massive and luminous stars known, at 215 M_☉ and 6.2 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 (30 Doradus) 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 10,000 times fainter and can only be resolved using speckle interferometry.

A near infrared image of the R136 cluster, obtained at high resolution with the MAD adaptive optics instrument at ESO’s Very Large Telescope. R136a1 is resolved at the center with R136a2 close by, R136a3 below right, and R136b to the left.
**Credit**: *ESO*/*VLT*

TABLE

Observation data
Epoch J2000.0 Equinox J2000.0
Constellation
Dorado
Right ascension
5h 38m 42.39s[1]
Declination
−69° 06′ 02.91″[1]
Apparent magnitude (V)
12.23[1]
Characteristics
Evolutionary stage
Wolf–Rayet star
Spectral type
WN5h[2]
B−V color index
0.03[1]
Astrometry
Distance
163,000 ly
(49,970[3] pc)
Absolute magnitude (MV)
−8.18[4]
Details[4]
Mass
215+45
−31 M☉
Radius
39.2 R☉
Luminosity
6,166,000 L☉
Surface gravity (log g)
4.0[5] cgs
Temperature
46,000±2,500 K
Rotational velocity (v sin i)
190 km/s
Age
1.0±0.2 Myr
Other designations
BAT99 108, RMC 136a1, HSH95 3, WO84 1b, NGC 2070 MH 498, CHH92 1, P93 954
Database references
SIMBAD
data