What is the hottest star in the Milky Way?

When we talk about large stars, lets make sure we know what we mean. Do you mean the brightest, largest in circumference or largest in terms of mass (heaviest) ?? There are less massive starts, which outshines more massive cousins and as stars go through their life cycle, at times they can expand dramatically (larger circumference) just prior to dying.

The most massive star is generally thought to be the Pistol star near the center of our galaxy. This being said, we have not found all the stars in our galaxy yet, and larger (more massive) stars could still be found.