The thermodynamics of collapsing molecular cloud cores using smoothed particle hydrodynamics with radiative transfer

• Published in: Monthly notices of the Royal Astronomical Society Vol. 367; no. 1; pp. 32 - 38
• Main Authors: Whitehouse, Stuart C., Bate, Matthew R.
• Format: Journal Article
• Language: English
• Published: 23 Ainslie Place, Edinburgh EH3 6AJ, UK. Telephone 226 7232 Fax 226 3803 Blackwell Science Ltd 01.03.2006; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Atoms & subatomic particles; Clouds; Earth, ocean, space; Exact sciences and technology; hydrodynamics; methods: numerical; Molecules; Radiation; radiative transfer; stars: formation; Thermodynamics; Collapse; Spherical symmetry; Molecular clouds; Smoothed particle hydrodynamics method; Heat capacity; Numerical method; hydrodynamics; methods: numerical; Specific heat; Thermodynamics; stars: formation; Equations of state; Initial conditions; Star formation; Radiative transfer; Opacity; Diffusion; Flux transfer
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2005.09950.x

We present the results of a series of calculations studying the collapse of molecular cloud cores performed using a three-dimensional smoothed particle hydrodynamics code with radiative transfer in the flux-limited diffusion approximation. The opacities and specific heat capacities are identical for each calculation. However, we find that the temperature evolution during the simulations varies significantly when starting from different initial conditions. Even spherically symmetric clouds with different initial densities show markedly different development. We conclude that simple barotropic equations of state like those used in some previous calculations provide at best a crude approximation to the thermal behaviour of the gas. Radiative transfer is necessary to obtain accurate temperatures.