An Agent-Based Model of the Stellar Mass Distribution

The Initial Mass Function (IMF) describes the distribution of stellar masses formed in a stellar cluster and constitutes a fundamental constraint for theories of star formation. In this work, we investigate the emergence of the IMF slope using a minimal agent-based model inspired by preferential attachment mechanisms. The model represents stars as accretion centers embedded in a reservoir of infalling material, where mass growth occurs through competitive accretion at a rate proportional to a tunable power of the stellar mass, and where fragmentation of accretion centers is allowed. We systematically explore the effects of accretion and fragmentation probabilities on the resulting mass distribution. The simulations show that competitive accretion alone leads to the dominance of a single massive object, whereas the inclusion of fragmentation regulates mass growth and produces a stable mass spectrum. For a specific range of accretion exponents, the resulting stellar mass function exhibits a logarithmic slope close to the Salpeter value. These results indicate that the interplay between fragmentation and mass-dependent accretion can produce a power-law slope comparable to the observed IMF under the simplified assumptions of the proposed agent-based model.