An unknown gas in which each molecule has mass \( 0.69 \times 10^{-26} \, \text{kg} \) escaped from a planet at a temperature \( T \). The radius of the planet is \( 18 \times 10^5 \, \text{m} \), acceleration due to gravity is \( 10 \, \text{m/s}^2 \), and the Boltzmann constant is \( 1.38 \times 10^{-23} \, \text{J/K}^{-1} \). The temperature \( T \) is: