GK

gigakelvin

Temperatureexact by definition

A gigakelvin is 10⁹ K exactly. Nuclear astrophysics lives here and has its own shorthand for it: T₉, meaning temperature in units of 10⁹ K. Silicon burning in a massive star runs near 3 GK, and core collapse pushes past 10.

1 GK 999,999,730 °C