[seth (OP)]

What is the Hayashi Model? What does it stay about gravitational stability?

[Soul Surfer]

The question you are asking does not come within the normal range of currently mainstream theories.  Please can you give references from which you learned about this model and expand your question slightly

[Soul Surfer]

I have had time to do a bit of research and this is the best reference I have come up with.

http://clairvoyance.dip.jp/pdf/Yamoto_(Doctoral_Thesis).pdf

This and other papers that quote elements of the question you asked deal with observational research and modelling of the processes that are involved in the formation of planetary systems around stars and notably the solar system itself.  This is a topic inwhich I have a considerable interest.

Initially the particles thrown out by supernovae are very finely divided and mixed up in the gas and dust and although the process of further accretion by relatively large bodies with sufficient self gravitation can be understood the processes by which the very fine dust gradually accretes to be big enough to self gravitiate are far from clear.  someindications of how this might occur comes from chondritic meteorites which show a lumpy structure in which some of the materials are partially differentiated.  The Hayashi model was originated in the early 1980s and looks at compositions and processes for aggregation of lumps.

The process is probably very complicated and involves electric and magnetic fields associated with photoionisation and heat from the newly formed star as well as gravitiational processes.