What is the most massive known star in the universe?

The most massive known star in the universe is R136a1. It is located in the R136 star cluster in the Tarantula Nebula, which is in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. R136a1 has an estimated mass of 315 times that of the sun, making it about 50% more massive than the previous record holder, which was also located in the R136 cluster.

Massive stars like R136a1 have a profound impact on their surroundings. They emit intense radiation and strong stellar winds, and eventually explode as supernovae. These explosions can produce heavy elements like gold and uranium, which are dispersed into space and eventually become the building blocks of new stars and planets. Understanding the behavior of massive stars like R136a1 is therefore crucial to our understanding of the evolution of the universe as a whole.