The role of the turbulence driving mode for the Initial Mass Function by Sajay Sunny Mathew et al. on Monday 28 November

Turbulence is a critical ingredient for star formation, yet its role for the

initial mass function (IMF) is not fully understood. Here we perform

magnetohydrodynamical (MHD) simulations of star cluster formation including

gravity, turbulence, magnetic fields, stellar heating and outflow feedback to

study the influence of the mode of turbulence driving on IMF. We find that

simulations that employ purely compressive turbulence driving (COMP) produce a

higher fraction of low-mass stars as compared to simulations that use purely

solenoidal driving (SOL). The characteristic (median) mass of the sink particle

(protostellar) distribution for COMP is shifted to lower masses by a factor of

~ 1.5 compared to SOL. Our simulation IMFs capture the important features of

the observed IMF form. We find that turbulence-regulated theories of the IMF

match our simulation IMFs reasonably well in the high-mass and low-mass range,

but underestimate the number of very low-mass stars, which form towards the

later stages of our simulations and stop accreting due to dynamical

interactions. Our simulations show that for both COMP and SOL, the multiplicity

fraction is an increasing function of the primary mass, although the

multiplicity fraction in COMP is higher than that of SOL for any primary mass

range. We find that binary mass ratio distribution is independent of the

turbulence driving mode. The average specific angular momentum of the sink

particles in SOL is a factor of 2 higher than that for COMP. Overall, we

conclude that the turbulence driving mode plays a significant role in shaping

the IMF.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2208.08802v2