DO CLOUD-CLOUD COLLISIONS TRIGGER HIGH-MASS STAR FORMATION? I. SMALL CLOUD COLLISIONS

Abstract

We performed sub-parsec (~0.06pc) scale simulations of two idealised\nmolecular clouds with different masses undergoing a collision. Gas clumps with\ndensity greater than 1e-20 g/cm3 (0.3e4 cm-3) were identified as pre-stellar\ncores and tracked through the simulation. The colliding system showed a partial\ngas arc morphology with core formation in the oblique shock-front at the\ncollision interface. These characteristics support NANTEN observations of\nobjects suspected to be colliding giant molecular clouds (GMCs). We\ninvestigated the effect of turbulence and collision speed on the resulting core\npopulation and compared the cumulative mass distribution to cores in observed\nGMCs. Our results suggest that a faster relative velocity increases the number\nof cores formed but that cores grow via accretion predominately while in the\nshock front, leading to a slower shock being more important for core growth.\nThe core masses obey a power law relation with index gamma = -1.6, in good\nagreement with observations. This suggests that core production through\ncollisions should follow a similar mass distribution as quiescent formation,\nalbeit at a higher mass range. If cores can be supported against collapse\nduring their growth, the estimated ram pressure from gas infall is of the right\norder to counter the radiation pressure and form a star of 100Msun.\n