HR: 1340h
AN: SA13A-1128    [Abstracts]
TI: Formation of Organic Molecules in Photo-evaporating Pre-planetary Disks
AU: * Throop, H
EM: throop@boulder.swri.edu
AF: SWRI, 1050 Walnut St Ste 400, Boulder, CO 80304
AU: Bally, J
EM: bally@casa.colorado.edu
AF: U. Colorado / CASA, UCB 389, Boulder, CO 80309
AU: Snow, T
EM: tsnow@casa.colorado.edu
AF: U. Colorado / CASA, UCB 389, Boulder, CO 80309
AB: A significant fraction of stars forming today are born in dense OB associations such as Orion. Photo-evaporation by the UV radiation of nearby O and B stars can destroy disks around low-mass stars on $10^5-10^6$ yr time-scales, dramatically affecting the formation of planets. However, the very same UV radiation that destroys the disks may also encourage the formation of organic molecules in these disks. UV photolysis of ices has been shown to produce solid-phase organic molecules, from simple CO and CH$_4$ to amino acids and alcohols (e.g., Bernstein et al 2002). If these compounds -- and the circumstellar disk in which they are formed -- can survive photo-evaporation, then they could play a role as biotic precursors. We have modeled the formation and loss rates for simple organic molecules produced in UV-irradiated circumstellar disks. The stability of these molecules depends on their location within the disk and the time delay between disk formation and the onset of photo-evaporation. We will identify the parameters of circumstellar disks which are most likely to allow formation and retention of organic compounds.
DE: 5455 Origin and evolution
DE: 6006 Atmospheres--evolution
DE: 6040 Origin and evolution
DE: 6215 Extraterrestrial materials
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting