Re: Dirty Snowball Worlds

On 2008-02-23, Tux Wonder-Dog <wes.parish@[EMAIL PROTECTED]
> wrote:
> Which does raise the question - is it likely that a planet so close
> to its star, likely to be 1:1 tidally locked?  Dole thought it
> likely, but most of the planets in so close that have been observed
> so far, have highly eccentric orbits

Well, the ones *very* close in do have highly circular orbits due to
tidal effects. They would not likely qualify as candidate "snowball"
worlds though, even on the cold side.

The rest of the planets we've observed - close or not - have had much
greater eccentricities than in our solar system.  Our observations are
very selective, but I don't immediately see why the planets that we
can detect should be much more likely to have eccentric orbits than
those we can't.

There has been some work done on simulating the dynamical evolution of
planetary systems.  One study (http://arxiv.org/abs/astro-ph/0703160)
found a very close fit to observed eccentricities of extrasolar
planets without much dependence upon initial conditions or requirement
for arbitrary parameters.

In that respect it seems that our solar system is *very* atypical in
the low eccentricities of its planets.


- Tim