Hi Larry

Jeans theory relied on a near miss with a random field star - a low probability event. It also dragged material out of the Sun, but it was soon shown to be far too hot to undergo Jeans collapse.

Woolfson updated the idea by making the other star the source of the material of the planets, and then looked at the probability of interactions during the high density nebula phase of the Sun's birth. Most - if not all - stars are born in similar high density nebulae. According to Woolfson's work stars with planets are roughly 20% of stars.

That being said there's nothing stopping other modes of planet formation, especially direct collapse like Alan Boss's scenario that's been touted as being the mechanism in low metallicity stars. Disk accretion scenarios probably work too, but they don't explain the momentum distribution of the Sun and planets, and that's the main motivation behind Woolfson's theory. In more recent papers Woolfson has moved towards hybrid scenarios in which tidal interactions cause planet formation in pre-existing disks around stars, and this idea in particular has been gaining ground among a lot of researchers.

The Universe will doubtless use all three because they're all viable physical mechanisms - the next stage in cosmogony will be to work out their relative frequency.

Adam