Temperatures hotter than the interiors of stars

The interior of stars, man... in the core of a heavy star in the final stages of its development, by the time Si burning sets in, temperature is higher than that - the iron core that forms in the end (before the supernova explosion) can get to 10 billion K. Granted, such a state doesn't last for longer than a day or two, but if a neutron star is born in the process, its core temperature will be in the same range.

But if we are talking normal (main-sequence) stars, the Sun's core is probably 15 million K, the heaviest O stars would have one around 50 million K - now that is too low for comparison, tokamaks like JET exceeded that already by an order of magnitude.

_{*Lunatic*, n.
One whose delusions are out of fashion.}