Protostars and Planets VI, Heidelberg, July 15-20, 2013
The Thermal Structures of Protostellar Envelopes in Isolated vs. Clustered Environments
Zhang, Yichen (Yale University)
Tan, Jonathan (University of Florida)
The star-forming environments affect various properties of the protostellar envelopes including their thermal structures, which in turn affect the chemical composition of the planetary disks and the planet formation. For example, comparing these processes in clustered regions with the high pressure like Orion region, to those in lower-pressure regions like Taurus cloud where stars form more sparsely in relative isolation. The formation of the planet in the solar system might also have been affected in such a way by its formation environment. If the protostellar cores are in approximate virial and pressure equilibrium with their surrounding clump medium, the Turbulent Core model explicitly links the structure and the evolution of such a core to the pressure of the surrounding environments. We have constructed a model based on the Turbulent Core model, starting with a pressure confined core, and self-consistently including an inside-out expansion wave, a rotating infall envelope, an accretion disk, and a bipolar magneto-hydrodynamic accretion-powered disk wind that sweeps up outflow cavities. The evolution of these components is also consistently considered. We perform continuum radiation transfer simulation to calculate the temperature structures and the spectral energy distribution and images as well. For massive star formation our model has successfully explained multiwavelength observations of a massive protostar G35.2-0.74. For low-mass star formation, it predicts significant differences in the envelope temperature in environments with high and low pressures. The typical temperature is ∼35K in a core in Orion-like environment and ∼15K in a core in Taurus-like environment. This difference is caused by different density, accretion rate, luminosity of the protostar and disk, and the intensity of the outflow in these two cases, and potentially can affect the chemical processes in the collapsing core and the planetary disk.
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