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The Formation and Survival of Water in the Terrestrial-Planet Forming Zone

Tuesday, January 12, 2010 - 4:00pm

CCU Lecture Series, National Radio Astronomy Observatory, Charlottesville


Edwin Bergin

Associate Professor of Astronomy

University of Michigan, Ann Arbor, MI 48109


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Despite its fundamental importance for life, the origin of water on our planet remains a mystery. Recent astronomical observations have revealed what may prove to be the ubiquity of water vapor during the early stages of planet formation. In this talk we will explore a simple solution that shows that this water vapor forms in situ and is capable of protecting itself from molecule-destroying stellar ultraviolet radiation. We will outline new aspects regarding the dominance of Lyman alpha photons in the radiation field and how the water chemistry compensates for water destruction by these photons. We will also discuss some of the implications of this result. The absorption of this radiation can control the gas thermodynamics in the upper layers of the protoplanetary disk. Similar to the Earth's ozone layer, which shelters the chemistry of life, the water layer protects other molecules and allows for the presence of a rich organic chemistry. More broadly, the survival of thousands of oceans in the natal habitable zone potentially allows it to be incorporated into forming planetesimals.