J/A+A/517/A60 Absorption coefficient of polystyrene (Kannuchova+, 2010)
Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra.
Kannuchova Z., Baratta G.A., Garozzo M., Strazzulla G.
<Astron. Astrophys. 517, A60 (2010)>
=2010A&A...517A..60K 2010A&A...517A..60K
ADC_Keywords: Atomic physics ; Minor planets
Keywords: minor planets, asteroids: general - methods: laboratory -
techniques: spectroscopic
Abstract:
The surfaces of airless bodies in the Solar System are continuously
altered by the bombardment of micrometeoroids and irradiation by solar
wind, flares, and cosmic particles. Major effects of this process -
space weathering - are darkening and "reddening" of the spectra of
surface materials, as well as a "degrading" of absorption features.
We studied the changes induced by energetic ion irradiation in the
ultraviolet-visual-near-infrared (UV-Vis-NIR) (0.2-0.98um)
reflectance spectra of targets selected to mimic the surfaces of
airless bodies in the inner Solar System. Our chosen targets are
olivine pellets, pure or covered by an organic polymer (polystyrene),
which is transparent before irradiation. Polystyrene is used as a
template for organic matter of low volatility that can be present on
asteroidal surfaces. Moreover we measured the changes induced by ion
irradiation in the absorption coefficient of the polymer. The purpose
was to have a tool to better compare laboratory with observed spectra
and distinguish between planetary objects with pure silicate surfaces
and those whose surface is covered by organic matter exposed to cosmic
ion bombardment.
Description:
The samples were irradiated in vacuum, at room temperature, with
200keV protons or 200-400keV argon ions. Before, during, and after
irradiation diffuse reflectance spectra were acquired. Polystyrene
films were also deposited on quartz substrates and irradiated while
transmittance spectra were recorded.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
absar.dat 93 925 *Absorption coefficient of polystyrene in the
wavelength range 250-980nm after irradiation
with 400keV Ar++
absh.dat 80 960 *Absorption coefficient of polystyrene in the
wavelength range 250-980nm after irradiation
with 200keV H+
--------------------------------------------------------------------------------
Note on absar.dat and absh.dat: dose is the total energy absorbed.
--------------------------------------------------------------------------------
See also:
http://web.ct.astro.it/weblab/dbindex.html :
Experimental Astrophysics Laboratory Home Page
Byte-by-byte Description of file: absar.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.2 nm lambda [250,980]?=- Wavelength
8- 21 E14.10 cm-1 Abs.coef1 ?=- Absorption coefficient for
fluence=6.3x1012ions/cm2, dose=1.5eV/16u
23- 36 E14.10 cm-1 Abs.coef2 ?=- Absorption coefficient for
fluence=3.8x1013ions/cm2, dose=9.1eV/16u
38- 51 E14.10 cm-1 Abs.coef3 ?=- Absorption coefficient for
fluence=7.5x1013ions/cm2, dose=18.3eV/16u
53- 65 E13.10 cm-1 Abs.coef4 ?=- Absorption coefficient for
fluence=1.5x1014ions/cm2, dose=36.5eV/16u
67- 79 E13.10 cm-1 Abs.coef5 ?=- Absorption coefficient for
fluence=6.0x1014ions/cm2, dose=146eV/16u
81- 93 E13.10 cm-1 Abs.coef6 ?=- Absorption coefficient for
fluence=5.2x1015ions/cm2, dose=1274.8eV/16u
--------------------------------------------------------------------------------
Byte-by-byte Description of file: absh.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.2 nm lambda [250,980]Wavelength
8- 21 E14.10 cm-1 Abs.coef1 ?=- Absorption coefficient for
fluence=2.5x1014ions/cm2, dose=6.6eV/16u
23- 36 E14.10 cm-1 Abs.coef2 ?=- Absorption coefficient for
fluence=2.0x1015ions/cm2, dose=52.7eV/16u
38- 51 E14.10 cm-1 Abs.coef3 ?=- Absorption coefficient for
fluence=4.0x1015ions/cm2, dose=105.5eV/16u
53- 66 E14.10 cm-1 Abs.coef4 ?=- Absorption coefficient for
fluence=8.0x1015ions/cm2, dose=211.0eV/16u
68- 80 E13.10 cm-1 Abs.coef5 ?=- Absorption coefficient for
fluence=1.6x1016ions/cm2, dose=422.0eV/16u
--------------------------------------------------------------------------------
History:
Copied at http://web.ct.astro.it/weblab/dbindex.html
(End) Patricia Vannier [CDS] 09-Aug-2010