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Delivery of Volatiles to Habitable Planets in Extrasolar Planetary SystemsThe Earth can support life because: (1) its orbit lies in the Sun's habitable zone', and (2) it contains enough volatile material (e.g. water and organics) for life to flourish. However, it seems likely that the Earth was drier when it formed because it accreted in a part of the Sun's protoplanetary nebula that was too hot for volatiles to condense. If this is correct, water and organics must have been delivered to the habitable zone, after dissipation of the solar nebula, from a 'wet zone' in the asteroid belt or the outer solar system, where the nebula was cool enough for volatiles to condense. Material from the wet zone would have been delivered to the Earth by Jupiter and Saturn. Gravitational perturbations from these giant planets made much of the wet zone unstable, scattering volatile-rich planetesimals and protoplanets across the Solar System. Some of these objects ultimately collided with the inner Planets which themselves lie in a stable part of the Solar System. Giant planets are now being discovered orbiting other sunlike stars. To date, these planets have orbits and masses very different from Jupiter and Saturn, such that few if any of these systems is likely to have terrestrial planets in the star's habitable zone. However, new discoveries are anticipated due to improved detector sensitivity and the increase in the timespan of observations. Here we present numerical experiments examining the range of giant-planet characteristics that: (1) allow stable terrestrial Planets to exist in a star's habitable zone, and (2) make a large part of the star's wet zone weakly unstable, thus delivering volatiles to the terrestrial planets over an extended period of time after the dissipation of the solar nebula.
Document ID
20010000047
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Chambers, John E.
(NASA Ames Research Center Moffett Field, CA United States)
Kress, Monika E.
(NASA Ames Research Center Moffett Field, CA United States)
Bell, K. Robbins
(NASA Ames Research Center Moffett Field, CA United States)
Cash, Michele
(Abraham Lincoln High School San Jose, CA United States)
DeVincenzi, Donald L.
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Subject Category
Lunar And Planetary Science And Exploration
Meeting Information
Meeting: Astrobiology Science
Location: Moffett Field, CA
Country: United States
Start Date: April 3, 2000
End Date: April 5, 2000
Funding Number(s)
PROJECT: RTOP 344-37-22-07
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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