Radiative transfer in very optically thick circumstellar disks

By M. Min, C. Dullemond, C. Dominik, A. D. Koter, J. Hovenier. 2009

173 citations recorded by the source corpus.

Aims. In this paper we present two efficient implementations of the diffusion approximation to be employed in Monte Carlo computations of radiative transfer in dusty media of massive circumstellar disks. The aim is to improve the accuracy of the computed temperature structure and to decrease the computation time. The accuracy, efficiency, and applicability of the methods in various corners of parameter space are investigated. The effects of using these methods on the vertical structure of the circumstellar disk as obtained from hydrostatic equilibrium computations are also addressed. Methods. Two methods are presented. First, an energy diffusion approximation is used to improve the accuracy of the temperature structure in highly obscured regions of the disk, where photon counts are low. Second, a modified random walk approximation is employed to decrease the computation time. This modified random walk ensures that the photons that end up in the high-density regions can quickly escape to the lower density regions, while the energy deposited by these photons in the disk is still computed accurately. A new radiative transfer code, MCMax, is presented in which both these diffusion approximations are implemented. These can be used simultaneously to increase both computational speed and decrease statistical noise. Results. We conclude that the diffusion approximations allow for fast and accurate computations of the temperature structure, vertical disk structure and observables of very optically thick circumstellar disks.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/41f696b060219e9b4eab87d1f387ccdbd04c32a3

How researchers see this paper

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In Astronomy and Astrophysics

1. Simon Bruderer
2. G. Herczeg
3. E. Dishoeck
4. C. Dullemond
5. Th. Henning
6. S. Doty
7. M. Benisty
8. Maarten Baes

In Atmospheric Science

1. Simon Bruderer
2. C. Dullemond
3. S. Doty
4. G. Herczeg
5. C. Pinte
6. E. Dishoeck
7. F. Ménard
8. K. Gordon

Citations in the corpus

• Shadows and spirals in the protoplanetary disk HD 100453 (2016, methodology): “We use the 3D version of the continuum radiative transfer code MCMax (Min et al. 2009) which calculates the thermal structure of the disk and produces ray-traced images.”
• The Inner Regions of Protoplanetary Disks (2010, methodology): “Improvements in the efficiency of these methods, however, have made this problem less serious in recent years (see e.g. Min et al. 2009 and Pinte et al. 2009).”
• The warm gas atmosphere of the HD 100546 disk seen by Herschel - Evidence of a gas-rich, carbon-poor atmosphere? (2012, methodology): “We thus implement the diffusion approximation derived in Robitaille (2010), based on Min et al. (2009).”
• Three-Dimensional Dust Radiative Transfer ∗ (2013, methodology): “Another possibility is to store the information for each cell and create the images at the end of the simulation (see, e.g., Dullemond & Turolla 2000, Min et al. 2009, Pinte et al. 2006).”
• Three Radial Gaps in the Disk of TW Hydrae Imaged with SPHERE (2016, methodology): “Radiative transfer code and modeling approach We employed the 2D version of the radiative transfer code MCMax by Min et al. (2009), which was also used by Menu et al. (2014, hereafter M14).”
• Survival of molecular gas in cavities of transition disks - I. CO (2013, methodology): “In order to improve the accuracy of the dust temperature in very optically thick midplanes and to speed up the calculation, we have replaced the modified random walk (MRW) approach (Min et al. 2009; Robitaille 2010) by the solution of the diffusion equation.”