The future of low-mass condensations in a core of molecular cloud

Abstract

Two scenarios have been proposed for evolution of star forming cores: gravitational fragmentation of larger structures and coalescence of smaller entities which are formed from some instabilities. Here, we turn our attention to the latter idea to investigate the evolution of observed low-mass condensations (LMCs) in the cores of molecular clouds. For this purpose, we implement the evolution of the observed LMCs of Taurus molecular cloud~1 (TMC-1). The core is modeled as a contracting cylinder with randomly spawned condensations in the middle region around its axis. For advancing bodies in their trajectories, we represent the acceleration of a particular LMC in terms of a fourth-order polynomial using the predictor-corrector scheme. Whenever two LMCs collide, they are assumed to be merged in one large condensation containing all the masses of the two progenitors. Implementations of many computer experiments with a wide variety of the free parameters show that the LMCs merge to form star-forming regions in the core. The results show that the total mechanical energy of the core increases by time, and its rate of increasing decreases by facilitating the merger. Finally, the mass spectrum index and goodness-of-fit are determined with 50% error in the number of mass points. The results show that the goodness-of-fit will be refined at the end of simulations, and the mass spectrum index inclines to the observed values for the moderate mass objects. The simulations show that the TMC-1 turns about 40% of its mass into cluster of dynamically unstable protostellar cores. In general, we suggest that the future of LMCs in a core of molecular cloud is merger to convert about half of its initial masses into a cluster of gravitationally unstable protostellar cores.