Thermal structure of a protostellar envelope

Abstract

A numerical hydrodynamical model for the evolution of spherically symmetric collapsing clouds, designed for the calculation of the thermal structure of these objects in both the prestellar and protostellar stages of their evolution, is presented. Distinctive features of the model include the possibility of independently describing the temperatures of the gas and dust, which is extremely important when calculating the thermal structure of prestellar and protostellar clouds, and the account of the radiation flux from the central protostar. This model is used to compare the theoretical density and temperature distributions with observations for nearby sites of star formation obtained with the Herschel Space Observatory. Application of the diffusion approximation with a flux limiter describes well the radial density and temperature distributions in protostellar clouds. However, significant differences between the model and observational density profiles were found for prestellar stages, suggesting the presence of appreciable deviations from equilibrium in the prestellar clouds. An approximate method for calculating the thermal structure of a cloud based on the adaptive $\tau$-approximation is presented. Application of the $\tau$-approximation yields good agreement with the diffusion approximation for the prestellar phase, but produces appreciable discrepancies for the protostellar phase, when the thermal structure of the accreting envelope is determined by the radiation of the protostar.

References in corpus (5)

• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• The Effects of Radiative Transfer on Low-Mass Star Formation
• The Earliest Phases of Star formation observed with Herschel (EPoS): The dust temperature and density distributions of B68
• Exposed Long-lifetime First-core: A New Model of First Cores Based on Radiation Hydrodynamics
• New Self-Similar Solutions of Polytropic Gas Dynamics

Cited by in corpus (3)

• Combining radiative transfer and diffuse interstellar medium physics to model star formation
• Influence of Photoelectrons on the Structure and Dynamics of the Upper Atmosphere of a Hot Jupiter
• Improving the thin-disk models of circumstellar disk evolution. The 2+1-dimensional model