Thermohaline Convection in Stellar Interiors.

A quantitative theory of mixing induced by an inverted gradient of mean molecular weight is presented. This theory is applied to three stellar problems, with the following results: (1) during 3He burning in a 2 Io star the change of X3 between the center and surface is 0.002; (2) the mechanism proposed by Stothers and Simon is too short-lived to explain the p Cephei variables, and (3) after the initial ignition of 4He burning in a degenerate shell flash, the 4He core and the C sbell mix on a time scale greater than too years. The theory is checked by comparison with the laboratory experiment by Stommel and Faller quoted by Stern. The agreement is satisfactory. An important uncertainty in the theory is the ratio of length to width of a moving finger of matter.