Re: [FT] Jovian formation

G'day guys,

Just to through another "I know just enough astronomy to be dangerous"
into
the mix....

An article I read in New Scientist a fortnight ago discusses one of the
latest theories in planet formation and the positioning of the gas
giants.
Basically they form at about the position of Jupiter, but then
collisons,
near misses and gravitational interplay sees them migrate to more stable
spots. So far there's pretty good evidence to support Jupiter having
migrated in 0.5 AU and Uranus migrated out 5 AU over the first 100
million
years of the Solar System then they got to fairly stable positions and
stuck there. This theory is being further supported by the relative
positions of the new planets being found. In one system they've
uncovered
there's a big gas giant at 0.8 AU another at 1.5 AU and another at 2.3
AU
(or something like that I'll have to check the articale again), two of
the
three are in almost perfectly circular orbits, but the other one (middle
one if I remember correctly) is in a very elliptical orbit as that
matches
the best stable state (its inclination to the plane is VERY close to
that
predicted by this theory).

Bottom line, mathematicians get bored/awed and look for neat 'laws'
everywhere (I've been guilty of that on a few long train trips) and as
we
know more (n > 1 solar systems) we're going to have to re-write what we
know about planet formation anyway so just stick them little old planets
where ever you damn well like ;)

Cheers

Beth

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Elizabeth Fulton
c/o CSIRO Division of Marine Research
GPO Box 1538
HOBART 
TASMANIA 7001
AUSTRALIA
Phone (03) 6232 5018 International +61 3 6232 5018
Fax (03) 6232 5199 International +61 3 6232 5199

email: beth.fulton@marine.csiro.au