Do tides play a role in the determination of the pre-stellar core mass function?

Abstract

Recent studies have examined the role of tides in the star formation process. They suggest, notably, that the tides determine the characteristic mass of the stellar initial mass function (IMF) by preventing the collapse of density fluctuations that would become gravitationally unstable in the absence of the tidal field generated by a neighboring central mass. However, most of these studies consider the tidal collapse condition as a 1D process or use a scalar virial condition and thus neglect the anisotropy of the tidal field and its compressive effects. In the present paper, we consider a turbulence-induced density perturbation formed in the envelope of a central core. This perturbation is subject to a tidal field generated by the central core. We study its evolution taking dynamical effects and the anisotropy of the tides into account. Based on the general tensorial virial equations, we determine a new collapse condition that takes these mechanisms into account. We identify two regimes: (i) a weak tidal regime in which the dynamics of the perturbation is only slightly modified by the action of the tides and (ii) a strong tidal regime in which the density threshold for collapse can potentially be increased due to the combined effects of the tides and the rotational support generated by the tidal synchronization of the perturbation with the orbital motion. In the case of a turbulence-induced density perturbation formed in the vicinity of a first Larson core, we show that the density threshold above which the perturbation collapses is increased only for low-mass perturbations (less than 2.7 solar mass) and only by at most a factor of 1.5. We conclude that tides likely do not play a major role in the process of star formation or in the determination of the characteristic mass of the IMF. We propose an alternative explanation for the observed value of the characteristic mass of the IMF.

11 pages, 6 figures. Typo corrected in eq. 9. Missing factor 2

References in corpus (12)

• Analytical theory for the initial mass function: CO clumps and prestellar cores
• Tidal Disruption Events
• The sonic scale revealed by the world's largest supersonic turbulence simulation
• Variations of the stellar initial mass function in the progenitors of massive early-type galaxies and in extreme starburst environments
• The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated clouds
• The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores
• The dynamical evolution of molecular clouds near the Galactic Centre -- III. Tidally--induced star formation in protocluster clouds
• Identification of prestellar cores in high-mass star forming clumps via ${\mathrm{H}}_2{\mathrm{D}}^{+}$ observations with ALMA
• Transition from Coherent Cores to Surrounding Cloud in L1688
• On the origin of the peak of the stellar initial mass function: exploring the tidal screening theory
• Magnetic Field Structure of Dense Cores using Spectroscopic Methods
• The effect of tidal forces on the Jeans instability criterion in star-forming regions

Cited by in corpus (1)

• On the Jeans criterion for hydrostatic and infalling gas