A note on strong mass loss from early sun and warm and wet Mars

Recently, the possibility of strong mass loss from an early sun has been proposed in connection with the lithium depletion problem along with early solar system problems. However, the time scale for this enhanced mass loss is uncertain. Using an empirical relation for the dependence of the Martian surface temperature on solar luminosity and surface pressure, we find that the mass loss time scale for a 1.1 M sun should be about 1 × 10⁹ years or longer if Mars had liquid water on its surface 3.8 billion years ago. The minimum surface pressure on early Mars should be about 5 bars of CO₂.