Interesting chart.
What does “temperature” really mean at 100,000 km, or a quarter way to the Moon?
When there is for most intents and purposes no air, what does it mean to take temp at 100,000 km versus, say, 110,000 km?
"Temperature" is a far more slippery concept than most folks realize ...
In this case, it means that although there are very few molecules they are moving extremely fast (high energy per molecule). This equates to a very high temperature. That said, the total energy, or heat, in the atmosphere at that altitude is nearly nil due to the small number of particles.
At that altitude, a macroscopic object's (you, for example, in a space suit) thermal interaction with the universe is almost exclusively radiative heat transfer. You'll bake on the up-sun side and freeze on the down-sun side.