Escape of the Atmosphere of Rotating Planet

Abstract

The problems of escape of a planetary atmosphere is reviewed. Formulae are derive for the rates of loss of mass and angular momentum from a unit area and from the whole planetary surface. The resulting formulae are applied to find the residence times of H, O, N2, O2 and CO2 in Martian atmosphere. All constituents are so stable while hydrogen is never stable and cannot be retained to my extent. 9 years) if the root mean square velocity of the particle is less than the escape velocity Ve. Valuable discussions were given by (2-4). (5) treated the problem taking into account the effect of orbital motion. The effect of rotation of the planet was introduced by (6) who derived formulae for the rates of loss of mass and angular momentum per unit area of the surface. In this paper formulae are derived to find expressions for the rates of loss of mass and angular momentum per unit area f the surface (including higher order terms than obtained by Burke to applicable for higher rotational velocities), and for the total rates of loss of mass and angular momentum from the whole planetary surface. The two necessary conditions for escape are: 1) the spatial velocity Vs should be larger than the escape velocity Ve. 2) Negligible chance of undergoing collisions. This condition is satisfied at the critical level (base of the exosphere). If ro is the radius of the planet, the critical velocity required for the outgoing particles at a height z above the planet's surface to escape is