J/A+A/482/989 Spectropolarimetric model for Earth-like planets (Stam, 2008)
Spectropolarimetric signatures of Earth--like extrasolar planets.
Stam D.M.
<Astron. Astrophys. 482, 989 (2008)>
=2008A&A...482..989S 2008A&A...482..989S
ADC_Keywords: Planets ; Models ; Polarization
Keywords: polarization - techniques: polarimetric - stars: planetary systems -
radiative transfer - Earth
Abstract:
We present results of numerical simulations of flux F and degree of
polarization P of light that is reflected by Earth-like extrasolar
planets orbiting solar type stars. Our results are presented as
functions of the wavelength (from 0.3 to 1.0µm, with 0.001µm
spectral resolution) and as functions of the planetary phase angle. We
use different surface coverages for our model planets, including
vegetation and a Fresnel reflecting ocean, and clear and cloudy
atmospheres.
Description:
Numerically calculated scattering matrix elements a1 and b1 of 11
different types of Earth-like extrasolar planets are presented. Matrix
element a1 is proportional to the total flux that is reflected by the
exoplanet, matrix element b1 is proportional to the linearly polarized
flux. Also given is the ratio -b1/a1, which is the degree of linear
polarization of the light that is reflected by the exoplanet.
Each directory contains 91 ASCII files: one file for each planetary
phase angle. The phase angles range from 0 degrees ("a full planet")
to 180 degrees ("a new planet"), in steps of 2 degrees.
Files are labelled DDDAAN.txt, where DDD is the phase angle and
AA_N the model code (000fo0.txt for 0 degrees in forest_0 model,
000oc0.txt for 0 degrees in ocean_0 model,
000000.txt for 0 degrees in lambert000 model).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lambert000/* . 91 Lambertian surface, wavelength independent
surface albedo 0.0, cloudfree
lambert010/* . 91 Lambertian surface, wavelength independent
surface albedo 0.1, cloudfree
lambert020/* . 91 Lambertian surface, wavelength independent
surface albedo 0.2, cloudfree
lambert040/* . 91 Lambertian surface, wavelength independent
surface albedo 0.4, cloudfree
lambert060/* . 91 Lambertian surface, wavelength independent
surface albedo 0.6, cloudfree
lambert080/* . 91 Lambertian surface, wavelength independent
surface albedo 0.8, cloudfree
lambert100/* . 91 Lambertian surface, wavelength independent
surface albedo 1.0, cloudfree
forest_0/* . 91 Lambertian surface, wavelength dependent albedo
of forest, cloudfree
forest_1/* . 91 Lambertian surface, wavelength dependent albedo
of forest, completely cloudy
ocean_0/* . 91 Fresnel surface, wavelength independent
surface albedo 0.0, cloudfree
ocean_1/* . 91 Fresnel surface, wavelength independent
surface albedo 0.0, completely cloudy
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Byte-by-byte Description of file (#): lambert*/* forest*/* ocean*/*
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Bytes Format Units Label Explanations
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3- 9 F7.5 um lambda [0.3,1.0] Wavelength (1)
11- 22 E12.6 --- a1 Matrix element a1
25- 36 E12.6 --- b1 Matrix element b1
39- 48 F10.8 --- Pol Degree of linear polarization (ratio -b1/a1)
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Note (1): The wavelength ranges from 0.3 to 1.0 microns, with steps of 1nm
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Acknowledgements:
Daphne Stam, D.M.Stam(at)sron.nl
(End) Patricia Vannier [CDS] 29-Feb-2008