The Formation and Survival of Water in the Terrestrial-Planet Forming Zone
Edwin BERGIN
Univ. of Michigan
Résumé :
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 is
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.
