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12 -- Comets and primitive Asteroids: Their Role in Supplying Water and Pre-biotic Organics to Early Earths
WEDNESDAY, April 16, 2008: AFTERNOON
Michael Mumma
NASA Goddard Space Flight Center
Greenbelt, MD, USA
Description
The origin of terrestrial life may have required an exogenous source of water and pre-biotic organic material. The proto-Earth formed in a hot nebular region (~1000 K) where pre-planetary solids were depleted in several key elements found in biological systems (e.g., H, C, N, O). It then experienced further depletion through collision with a Mars-sized proto-planet, removing the primordial ocean and atmosphere and leaving the re-formed Earth severely depleted in low-Z elements relative to the nebular mean. A current view is that Earth's volatile inventory, including organic molecules, was subsequently replenished by in-fall of icy planetesimals, asteroids, and interplanetary dust during clearing of the early solar system (the declining heavy bombardment and the late heavy bombardment). This session invites contributions on dynamical models for delivery from possible source populations (comets and asteroids), the chemical and isotopic composition of those populations, the survival of delivered chemical fractions, possible experimental tests of such delivery, and astrobiological implications for planetary systems here and elsewhere.
ORAL SESSIONS
3:15 12-12-O. Chemical Diversity Among Comets: An Emerging Taxonomy Based
on Organic Composition [invited] M. Mumma
3:40 12-11-O. Origin of Earth's Water—Current Key Issues
[invited] K. Meech, M. Mottl
4:00 12-02-O. Deuterium Enrichment in Comets as a Test of Exogenous Delivery of
Water and Prebiotic Organic Matter to Early Earth B.P. Bonev, E.L. Gibb,
M.J. Mumma
4:15 BREAK
4:40 12-07-O. Ice Nearby: The Main Belt Comets [invited] D. Jewitt
5:00 12-09-O. Activated Asteroids in the Main Belt, Its Nature and Its Role as a
Possible Source of Terrestrial Water J. Licandro, J. de León, N. Pinilla-Alonso,
H. Campins, G.P. Tozzi, H. Boehnhardt
5:15 12-10-O. The Organic Composition of Carbonaceous Meteorites: Chemical
Analysis of Samples from the Asteroid Belt Z. Martins, O. Botta, M. Sephton,
P. Ehrenfreund
POSTERS
12-01-P. Swift Observations of Cometary X-ray and UV Emissions D. Bodewits, M. Mumma,
G. Brown, F.S. Porter, W.B. Landsman
12-03-P. Radio Observations of Recent Bright Comets S. Charnley
12-04-P. The Journey from the Main Belt to the Earth: the Near-Earth Asteroids and Their
Link with Meteorites J. de León, J. Licandro, D. Lazzaro, N. Pinilla-Alonso,
M. Serra-Ricart
12-05-P. Comparing Abundances of Oxidized Carbon Among Comets
M. DiSanti, B.P. Bonev, E.L. Gibb, K. Magee-Sauer, M.J. Mumma, G.L. Villanueva
12-06-P. Present Day Sources of Organic Delivery to Earth by Meteoroids
P. Jenniskens, J. Vaubaillon
12-08-P. The Effects of Oort Cloud Comet Showers on Earth N. Kaib, T. Quinn
12-13-P. High Rates of IDP-organics Delivery on the Ancient Terrestrial Planets with
Extended Hydrogen Atmospheres A.K. Pavlov, N.I. Dolindo, A.A. Pavlov
12-14-P. Water Ice Rich and Carbon Depleted TNOs and the Origin of the Carbon Depleted
Comets? N. Pinilla-Alonso, J. Licandro, R. Brunetto, R. Gil-Hutton
12-15-P. The Depleted Organic Composition of Comet C/2000 WM1 (LINEAR) and its
Contribution to Determining the Source of Water and Prebiotic Organics on
the Young Earth Y. Radeva, B.P. Bonev, M.J. Mumma, M.A. DiSanti, G. Villanueva,
K. Magee-Sauer, E.L. Gibb, N. Dello Russo, H.A. Weaver
12-16-P. Large Water Reservoirs in Asteroids A. Rowe, H. Campins, E. Martin, K. Hargrove
12-17-P. A Multiwavelength Approach to Understanding Chemical Heterogeneity and
the Parentage of Radical Species in Comets D.Walter, M. Mumma, M. A. DiSanti,
B.P. Bonev, R. Gelderman