* Brightest in the sky? That would be the Sun, but its brightness is due to its proximity to Earth, not its inherent temperature.
* Brightest by absolute magnitude (intrinsic brightness)? This is tricky, as it depends on what we mean by "brightest".
* Highest luminosity (total energy output)? This would likely be a massive, hot blue supergiant like R136a1, with a surface temperature around 53,000 K.
* Highest surface temperature? This is where things get interesting. While blue supergiants are hot, some smaller, denser stars like Wolf-Rayet stars can reach surface temperatures over 100,000 K. However, these stars are often relatively faint due to their small size.
Therefore, there isn't a single "brightest" star with a universal temperature. It depends on what criteria we use to define brightness.
