SURVIVAL-TIME OF PREPLANETARY NEBULAE DEBRIS

In a previous paper (Fierro, 1993) we suggested the possibility and the consequences of having planets, rings and ring arcs around planetary nebulae and the interactions they might have with the nebulae, concerning their morphology and chemical composition. In the present paper we calculate the survival time of an ice planet around a newly formed preplanetary nebula and the conditions that would have to exist in order for its evaporation to account for the OH molecules that produce OH maser emission observed in some possible progenitors.