R136a1 (short for RMC 136a1) is the most massive and luminous star known, at around 291 solar masses (M☉) and around 7.2 million times the Sun's luminosity (L☉). 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 100 times fainter than the cluster and can only be resolved using speckle interferometry.

Closest relatives