Unformatted text preview: etained from condensation
in early solar system evolution in outer system Comets
Comets ! Formation residue form solar nebula, in the outer solar system
Mostly ices (H2O, CH4, CO2, NH3, N2, other volatiles)
Substantial organic content, some light silicate components likely ! Highly variable in size !
! • ! Elliptical orbits
• ! Some comets follow highly elliptical or hyperbolic orbits taking them from the Kuiper / Oort
regions to the inner solar system
Majority are probably in stable orbits in their source regions, largely unseen Earth-crossing asteroids
• ! Range from meters to kilometers in diameter. Comets are essentially outer system analogs
of inner system primordial debris (e. g. asteroids, meteors) A few are probably desiccated remnants or cores of comets now in close solar orbit Organics
• Likely that Earth’s surface volatiles are largely attributable to cometary impacts during the
Late Heavy Bombardment (4.2 - 3.8 Ga)
Oceans, atmospheric CO2, N2
All inner planets were likely enriched initially with volatiles from comets...
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This document was uploaded on 04/05/2014.
- Spring '14