Hi LJK

Time to bite the bullet - the Capture theory is the only theory that explains the far-out Jovians naturally. Orbital scattering, applied to nebula or disk-instability theories, can explain it but the odds are low - orbits so close to parabolic/hyperbolic orbits are freakish, not natural. Capture theory posits some - if not all - planets are captured Jeans mass condensations from collapsing tidal filaments pulled off diffuse protostars and/or their disks. Thus some will be free-floaters and others will be on highly elliptical orbits prior to orbital round off (taking ~ millions of years) in a captured dust disk around the larger star. This is a natural feature of the theory and has been confirmed by observation. Other theories can tackle these observations - but as "epicycles", unnatural extensions from the basic theory. For capture theory these are natural outcomes, expected not freakish.

What Capture theory is yet to tackle is the observed metallicity correlation between stars and planets, which does make sense in some nebula theories. However the observed statistical background of ~ 3% stars with planets, regardless of metallicity, fits Capture theory and disk-instability. What's needed is a theoretical test that has an observational outcome to decide between the two. Capture theory doesn't depend on the cooling characteristics of a protostellar disk, but disk-instability does - if a disk can't cool efficiently Jeans Mass condensations in a disk don't survive. Tidal condensations in a distant filament are unaffected. This could be an observational test. Or direct observation of a condensing tidal filament?

Adam