Protoplanetaarisia

Protoplanetaarisia is a coined term referring to a proposed, speculative stage in the formation of planetary systems. In this concept, the early protoplanetary disk hosts a population of growing planetary embryos whose mutual gravity and interaction with the gaseous disk organize into a distinctive dynamical regime characterized by rapid accretion, migration, and the formation of resonant orbital configurations.

During protoplanetaarisia, solid material in the disk coagulates from dust to kilometer-sized planetesimals and then to planetary embryos. Gravitational interactions among embryos, combined with gas drag and disk torques, drive inward or outward migration and may lock bodies into resonant chains. Collisions and mergers among embryos build larger protoplanets, potentially giving rise to a system of closely spaced planets.

Observationally, protoplanetaarisia is not directly observed; it remains a theoretical construct. Researchers study it through numerical simulations of planet formation and by interpreting the architectures of mature exoplanet systems that show resonant or near-resonant configurations. The concept helps frame how initial conditions and disk properties influence the eventual distribution of planet masses and orbits.

The term is a neologism that appears in some theoretical discussions and, occasionally, in science fiction. It is not universally adopted in the planetary science literature, and its definition may vary across sources.