Asteroid Belt Placement May Be VERY Important for the Evolution of Exosolar Planetary Systems

Solar systems with life-bearing planets may be rare if they are dependent on the presence of asteroid belts of just the right mass, according to a study by Rebecca Martin, a NASA Sagan Fellow from the University of Colorado in Boulder, and astronomer Mario Livio of the Space Telescope Science Institute in Baltimore, Md.

They suggest that the size and location of an asteroid belt, shaped by the evolution of the sun's protoplanetary disk and by the gravitational influence of a nearby giant Jupiter-like planet, may determine whether complex life will evolve on an Earth-like planet.

This might sound surprising because asteroids are considered a nuisance due to their potential to impact Earth and trigger mass extinctions. But an emerging view proposes that asteroid collisions with planets may provide a boost to the birth and evolution of complex life.

Asteroids may have delivered water and organic compounds to the early Earth. According to the theory of punctuated equilibrium, occasional asteroid impacts might accelerate the rate of biological evolution by disrupting a planet's environment to the point where species must try new adaptation strategies.

The astronomers based their conclusion on an analysis of theoretical models and archival observations of extrasolar Jupiter-sized planets and debris disks around young stars. "Our study shows that only a tiny fraction of planetary systems observed to date seem to have giant planets in the right location to produce an asteroid belt of the appropriate size, offering the potential for life on a nearby rocky planet," said Martin, the study's lead author. "Our study suggests that our solar system may be rather special."

The findings will appear today in the Monthly Notices of the Royal Astronomical Society.

While the press release focuses on life bearing worlds, the really interesting bit is how the protoplanetary disk's make up, density and distribution really matter for the evoltuon of the  extrasolar planetary system.  

IF the hot jupiters migrated in, then this almost assuredly discounts anything other than other gas giants having life bearing worlds.  Amongst other things.

A model ought to be compared to Fomalhaut's disk and planets (frex) to see.  

A related art was sent in email, too.