Abstract
The flow induced around a sphere with a uniform temperature in a gas with a uniform temperature gradient is investigated for small KNUDSEN number on the basis of the linearized BOLTZMANN-KROOK-WELANDER equation. The velocity field is obtained up to the order of the KNUDSEN number cubed. The thermal force acting on the sphere is also obtained up to the third order, and the relation between its direction and the KNUDSEN number is discussed.