1970/12/01 by Takashi Kusaka, T. Kusaka, Takenori Nakano +2 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Solar and Space Plasma Dynamics
paper · doi:10.1143/ptp.44.1580
crossref issued 1970/12/01 · crossref published 1970/12/01 · crossref published-print 1970/12/01 · openalex publication_date 1970/12/01 · crossref created 2005/12/15 · crossref deposited 2017/08/24 · openalex created_date 2025/10/10 · crossref indexed 2026/07/29 · openalex updated_date 2026/07/30
Some processes which are expected to lead to the growth of solid particles in the primordial solar nebula are investigated for two evolutionary phases of the nebula; one is the early phase when the nebula was contracting nearly freely, and the other is the later phase after it flattened into a gaseous disk which is rotating about the protosun. For the free-fall phase, the collision between grains is found to be too infrequent to lead to their agglomeration for both of the two cases where the motion of grains is thermal or it shares the turbulent motion of the gas. For the disk phase, it is found that solid particles can hardly grow to a centimeter size even in 109 years if only the collision is considered. However, they are found to sink towards the equatorial plane of the disk in about 106 years to form a high density layer where their collision is greatly accelerated. The time of this sedimentation is independent of the luminosity of the protosun. When the density of this layer becomes greater than the Roche density, the fragmentation may occur to form the protoplanets. Finally, the effect of mass ejection from the protosun on the growth of solid particles is investigated.