R136a1

R136a1 is the most massive and luminous known star. It is a Wolf–Rayet star at the center of R136. 
R136 is the central group of stars of the large NGC 2070 open cluster in the Tarantula nebula. The nebula lies about 50 kiloparsecs (163,000 light-years) in the Large Magellanic Cloud. 
R136a1 has 265 the mass of the Sun, and 8.7 million times its luminosity. It is also one of the hottest at over 50,000 K. The cluster is only about 1.5 million years old, and is pouring out a huge amount of energy. Together, they outshine our Sun by a factor of 30 million.
The star is the largest of nine huge stars in the cluster.