Opacities for protoplanetary disks

This web page is devoted to various aspects of the calculation of Rosseland and Planck mean opacities for dusty systems under conditions, typical of protoplanetary accretion disks. We present an opacity code (written in Fortran 77), specifically developed for the application to hydrodynamical disk calculations and provide opacity and related data in tabulated forms and/or figures.

Earlier papers:

Here, we present a link to the opacity model of Henning & Stognienko, 1996, A+A, 311, 291-303. Bell, K.R., Cassen, P.M., Klahr. H.H., Henning, Th., 1997, ApJ, 486, 372 referred to the data in their paper (see Table 3 on the page 375).

Excessive information about our opacity table can be found in:

A description of the opacity model and applied numerical techniques. More information including comparison of the most common opacity models and study the influence of various opacity tables on the hydrodynamical structure of accretion disks is given in the paper by Semenov et al. (2003) Briefly, it is a continuation of the study by Henning & Stognienko (1996) that has been extended on composite and multishell (porous) dust grains. In addition, it includes up-dated optical constants for the silicates, new estimates on the mass fractions of dust grain constituents, and a table of molecular opacities from the Berlin group (Ch. Helling).

Optical constants of dust constituents that we used:

As dust components we considered olivine, orthopyroxene, iron, troilite, refractory organics as well as water ice. To test our code, we compared the results with calculations based on old refractive indices taken from the paper by Pollack et al., 1994, ApJ, 421, 615-639 and the Rosseland mean opacities, published there.

All other calculations have been performed for a new set of optical constants (partly taken from the paper by Henning & Stognienko 1996) and new values for silicates measured in the Jena laboratory.

Mass fractions and evaporation temperatures of dust materials that we used:

You can find the mass fractions of the dust constituents in Table 1 of our description. Their evaporation temperatures are adopted from the paper by Pollack et al. 1994 (see Table 3 therein). For illustrative purposes, we give a set of evaporation temperature values for gas density 10^-10 g/cm³ here.

Frequency-dependent (monochromatic) opacities:

We compiled a set of monochromatic opacity data for all considered dust models, namely, for composite and homogeneous aggregates as well as for (porous) composite and multishell spherical particles. The calculations have been performed for dust particles having a modified MRN distribution of sizes, where the modification consists in inclusion of large grains, up to 5 mkm. The archive file for the case of the "iron-poor" (Fe/[Fe+Mg]=0) silicate mineralogy is given here, for the case of the "iron-rich" (Fe/[Fe+Mg]=0.4) silicate mineralogy is given here, and for the case of the "normal" (Fe/[Fe+Mg]=0.3) silicate mineralogy is given here. In addition, you can check two representative figures of the monochromatic dust opacities in the case of the "iron-poor" and "iron-rich" silicates computed for low- (T<120 K) and high-temperature (T>700 K) regions of protoplanetary disks.

The Rosseland and Planck mean opacities:

We computed Rosseland and Planck mean opacities under physical conditions typical of protoplanetary disks, namely, for temperatures ranging from 5 to 10,000 K and densities between about 2*10^-18 g/cm³ and 2*10^-07 g/cm³. Our opacity table is freely available as a FORTRAN 77 code which can be downloaded here. The comparison between our results and the Rosseland (left panel) and Planck (right panel) mean opacities of most common models is made here. Depicted are the mean opacities composed of the NRM composite aggregates in the low temperature range and the gas opacity for the higher temperatures (solid line). Opacity tables of the OP project (Seaton et al. 1994, crosses), OPAL project (Iglesias & Rogers 1996, circles), Bell & Lin 1994 (dot-dashed line), Pollack et al. 1994 (open triangles), Alexander 1975 (line with open squares), and Alexander & Ferguson (dashed line) are shown.

Acknowledgements:

We thank D. Alexander for his opacity tables and valuable comments. This work has been supported by the DGF (Deutsche Forschnungsgemeinschaft).

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Created by R. Stognienko, Dec 1996

Last modification by Dmitry A. Semenov, March 2003