J/ApJS/210/21 Refractive indices of grain materials (Cuzzi+, 2014)
Utilitarian opacity model for aggregate particles in protoplanetary nebulae and
exoplanet atmospheres.
Cuzzi J.N., Estrada P.R., Davis S.S.
<Astrophys. J. Suppl. Ser., 210, 21 (2014)>
=2014ApJS..210...21C 2014ApJS..210...21C
ADC_Keywords: Interstellar medium ; Models
Keywords: opacity; planets and satellites: atmospheres; protoplanetary disks;
radiative transfer
Abstract:
As small solid grains grow into larger ones in protoplanetary nebulae,
or in the cloudy atmospheres of exoplanets, they generally form porous
aggregates rather than solid spheres. A number of previous studies
have used highly sophisticated schemes to calculate opacity models for
irregular, porous particles with sizes much smaller than a wavelength.
However, mere growth itself can affect the opacity of the medium in
far more significant ways than the detailed compositional and/or
structural differences between grain constituents once aggregate
particle sizes exceed the relevant wavelengths. This physics is not
new; our goal here is to provide a model that provides physical
insight and is simple to use in the increasing number of
protoplanetary nebula evolution and exoplanet atmosphere models
appearing in recent years, yet quantitatively captures the main
radiative properties of mixtures of particles of arbitrary size,
porosity, and composition. The model is a simple combination of
effective medium theory with small-particle closed-form expressions,
combined with suitably chosen transitions to geometric optics
behavior. Calculations of wavelength-dependent emission and Rosseland
mean opacity are shown and compared with Mie theory. The model's
fidelity is very good in all comparisons we have made except in cases
involving pure metal particles or monochromatic opacities for solid
particles with sizes comparable to the wavelength.
Description:
For ease of comparison with previously published results, we adopt
refractive indices, material abundances, and stability regimes for the
condensible constituents as published by Pollack et al.
(1994ApJ...421..615P 1994ApJ...421..615P).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig3.dat 120 100 Real and imaginary indices as used in our code
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See also:
J/A+A/540/A2 : Refractive index of hydrocarbon solids (Jones, 2012)
J/A+A/483/661 : Refractive index for silicon carbide (SiC) (Pitman+, 2008)
Byte-by-byte Description of file: fig3.dat
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Bytes Format Units Label Explanations
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1- 10 E10.4 cm lambda [5e-5/1] Wavelength 0.5µm≤λ<1cm)
12- 21 E10.4 --- rIce [1.3/1.8] Real index for water ice
23- 32 E10.4 --- iIce Imaginary index for water ice
34- 43 E10.4 --- rPyro [1.6/2.1] Real index for pyroxene
45- 54 E10.4 --- iPyro Imaginary index for pyroxene
56- 65 E10.4 --- rTro [2.5/64.7] Real index for troilite
67- 76 E10.4 --- iTro Imaginary index for troilite
78- 87 E10.4 --- rFe [3.1/2413] Real index for iron
89- 98 E10.4 --- iFe Imaginary index for iron
100-109 E10.4 --- rOrgan [1.6/2.3] Real index for organics
111-120 E10.4 --- iOrgan Imaginary index for organics
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 01-Apr-2014