It's difficult to definitively say which star is the *absolute* hottest in the universe, as we haven't observed every star. However, the title of "hottest known star" currently goes to WR 102, a Wolf-Rayet star located about 5,000 light-years away in the constellation Sagittarius.

Here's what we know about WR 102:

* Surface temperature: Estimated to be around 165,000 Kelvin (297,000 degrees Fahrenheit).

* Type: Wolf-Rayet stars are massive, hot, and very luminous stars that are in a late stage of their evolution. They are known for their powerful stellar winds and peculiar spectra.

* Rarity: Wolf-Rayet stars are extremely rare, making up only a tiny fraction of the Milky Way galaxy's stellar population.

While WR 102 is currently the hottest star we know of, it's possible that even hotter stars exist out there, waiting to be discovered. The constant advancements in astronomy and our understanding of stars mean this record might be broken in the future.