Migration of Phyllosilicates Through the Solar Nebula Could Explain Water-rich Planetary Formation

Research by Fred Ciesla, NASA Ames, Dante Lauretta, Lon Hood, LPL- U of Arizona: Funding: National Research Council, NASA Origins of Solar System Program

Shock waves through icy parts of the solar nebula may be the mechanism that enriched ancient meteorites (called chondrites) with water -- water that some believe provided an otherwise dry Earth with oceans.

Planetary scientists Fred J. Ciesla, Dante S. Lauretta and Lon L. Hood hypothesize that chondrule-forming shock waves in icy regions of the solar nebula (5 AU) could have produced conditions that allowed rapid mineral hydration. These phyllosilicates (particles that contain water) could have migrated to where the Earth currently resides in the solar system (1AU).

The Process:

Some chondritic meteorites contain phyllosilicates which are found in rims of chondrules. Chondrites, among the oldest and most primitive solar system materials, are believed to have formed within the solar nebula. These minerals also appear to have formed before being accreted onto the chondrules. Gas in the nebula slows as it passes through a shock front, increasing in temperature and density. Solid particles in the gas continue through the shock wave at high velocity. The solid particles heat up because they are speeding through the slower-moving gas. The gas both heats and slows the chondrules, so they melt and begin to cool. The water vapor then reacts with the dust to form hydrated silicates, and the chondrules accrete these silicates to form their rims.

Because the area where early Earth formed was too hot for water to be incorporated into a solid body, meteorites containing phyllosilicates may have delivered at least part of Earth's water. This scenario provides a mechanism to preserve organic material as observed in carbonaceous chondrite meteorites. If water reacted with fine dust in the solar nebula, temperatures in the meteorites would have remained low enough for organic molecules to survive and be delivered, along with water to Earth.

Significance to Solar System Exploration

This research provides insight into processes occurring during the formation of planetary systems and suggests that the material that went into forming the Earth (or any other planet) may not have been created at or near the same location as the Earth (or planet). Some materials could have formed elsewhere and then migrated large distances.

Chondrules are small silicate particles that make up large components of many of the meteorites that fall on Earth. They are believed to be the most primitive objects in the solar system. FGR stands for 'Fine Grained Rim' which can be seen and delineated

Understanding where different materials formed and how they were transported in the early solar system provides insight into how the planetary systems evolve.

Implications

This research provides a framework for explaining part of the early stage of terrestrial planet formation. It raises the question: "Are planets like Earth common or rare?"

For further information about science highlights and having your research highlighted, please contact Samantha Harvey at NASA's Jet Propulsion Laboratory, Samantha.K.Harvey@jpl.nasa.gov.

Science Features
NASA Science Highlights
Astrobiology Features
Power & Propulsion Features
Astronomy Features
Science & Technology Reports
Technology Features