Boreskov

“BUTTERFLY EFFECT” IN PLANETESIMAL FORMATION OR STUDYINGTHE OUTCOME OF GRAVITATIONAL INSTABILITY IN MULTIPHASEPROTOPLANETARY DISCStoyanovskaya O.P.Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia; stop@catalysis.ruOP‐42One of the most intriguing stages of matter self‐organization in biosphere evolution isabiogenic synthesis of primary prebiology substances, preceding RNA‐World. According toastrocatalysis hypothesis, most of Earth biosphere primary organic substance wassynthesized before Earth formation, under the conditions of circumsolar protoplanetary disc.Circumsolar disc evolution goes via growth of solid bodies – from nanometer dust grainsto kilometric‐sized planets. “Astrocatalysis” as a stage of chemical evolution coinsides withformation of large bodies (planetesimals and planet embryos) from metric size boulders –major bottleneck in the planet formation process. Planetesimal on the stage of itsemergence is considered as a clump of gas and solids whose gravitational field preserves itsmass when the clump moves. These self‐gravitating clumps can be suggested as chemicalreactors for efficient synthesis of prebiotic substance.Gravitational instabilities can play a key role in formation of collapsing clumps of gas andsolids. Although computer simulations show that development of gravitational instabilityoften resulted in global spiral structure formation without triggering to self‐gravitatingclumps formation. Several regimes of such clumps formation is described yet. In alldescribed modes collapsing object formation goes only under stiff (sometimes contradictoryfor real discs) limits on medium and physical process parameters. For evolving systems theprobability to strike the target of such conditions is nearly equal to zero.In our investigation we found new regime of self‐gravitating clumps formation. Selfgravitatingclumps can be formed by the development of “two‐phase” Jeans instability of gasand primary bodies medium. This instability reveals so‐called “butterfly effect” in two‐phasediscs when dynamics of the system is determined by collisionless collective motion of lowmassivesubdisc of primary solids.This implies that the possibility of clump formation is determined both by the rate of gascooling and its density redistribution and by the rate of large (over 1 m) primary solidsconcentration and decrease in dispersion of their velocities (cooling of primary solids). Thuswe managed to expand the area of sufficient conditions for collapsing clumps formation.103