TY - JOUR
T1 - Grain size effects on the infrared spectrum of mineral mixtures with dark components
T2 - New laboratory experiments to interpret low-albedo rocky planetary surfaces
AU - Poggiali, G.
AU - Fossi, L.
AU - Wargnier, A.
AU - Beccarelli, J.
AU - Brucato, J. R.
AU - Barucci, M. A.
AU - Beck, P.
AU - Matsuoka, M.
AU - Nakamura, T.
AU - Merlin, F.
AU - Fornasier, S.
AU - Pajola, M.
AU - Doressoundiram, A.
AU - Gautier, T.
AU - David, G.
N1 - Publisher Copyright:
© The Authors 2024.
PY - 2024/5/1
Y1 - 2024/5/1
N2 - Context. A number of bodies in the Solar System are characterized by dark surfaces, from carbonaceous asteroids to the enigmatic surface of Phobos and Deimos. Our understanding of the spectroscopic behavior of low-albedo surfaces remains incomplete. To improve the interpretation of remote sensing data, laboratory studies continue to serve as a pivotal tool for unveiling the physical state and composition of such surfaces. Aims. Several processes can be simulated in the laboratory, however, the preparation and analysis of a complex mixing of analog material is one of the most fundamental among them, while also being one of the most complex when multiple components are used. In this work, we aim to study how dark material mixed with basaltic material at different grain sizes can affect the spectroscopic features from the near- to mid- infrared (1.25–25 µm). Methods. Our sample set includes four series of basaltic mix (feldspar and pyroxene) at different grain sizes from <50 µm to 1000 µm, mixed with amorphous carbon at increasing weight percentages ranging from 1% to 50%. We analyzed several features on the spectrum of each mineral mixture. In particular, we investigated the behavior of the: (i) near-infrared slope; (ii) 2.7 µm OH-stretching band; (iii) Christiansen features; and (iv) Reststrahlen band and Transparency feature. Results. The measurements presented in this work, which take into account a large wavelength range for the first time, point toward a critical effect of dark material, but with a different outcomes for each grain size. Some of the most interesting results involve the slope trend of modification with dark material and the variant behavior of the Reststrahlen band and Transparency feature. Conclusions. This dataset will offer a key support in the interpretation of data collected on dark surfaces by past and future space missions. This knowledge will be also important in the context of linking analyses of returned samples with remote sensing data collected on planetary surfaces.
AB - Context. A number of bodies in the Solar System are characterized by dark surfaces, from carbonaceous asteroids to the enigmatic surface of Phobos and Deimos. Our understanding of the spectroscopic behavior of low-albedo surfaces remains incomplete. To improve the interpretation of remote sensing data, laboratory studies continue to serve as a pivotal tool for unveiling the physical state and composition of such surfaces. Aims. Several processes can be simulated in the laboratory, however, the preparation and analysis of a complex mixing of analog material is one of the most fundamental among them, while also being one of the most complex when multiple components are used. In this work, we aim to study how dark material mixed with basaltic material at different grain sizes can affect the spectroscopic features from the near- to mid- infrared (1.25–25 µm). Methods. Our sample set includes four series of basaltic mix (feldspar and pyroxene) at different grain sizes from <50 µm to 1000 µm, mixed with amorphous carbon at increasing weight percentages ranging from 1% to 50%. We analyzed several features on the spectrum of each mineral mixture. In particular, we investigated the behavior of the: (i) near-infrared slope; (ii) 2.7 µm OH-stretching band; (iii) Christiansen features; and (iv) Reststrahlen band and Transparency feature. Results. The measurements presented in this work, which take into account a large wavelength range for the first time, point toward a critical effect of dark material, but with a different outcomes for each grain size. Some of the most interesting results involve the slope trend of modification with dark material and the variant behavior of the Reststrahlen band and Transparency feature. Conclusions. This dataset will offer a key support in the interpretation of data collected on dark surfaces by past and future space missions. This knowledge will be also important in the context of linking analyses of returned samples with remote sensing data collected on planetary surfaces.
KW - methods: laboratory: solid state
KW - minor planets, asteroids: general
KW - planets
KW - planets and satellites: composition
KW - satellites: surfaces
KW - techniques: spectroscopic
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U2 - 10.1051/0004-6361/202347681
DO - 10.1051/0004-6361/202347681
M3 - Article
AN - SCOPUS:85192388378
SN - 0004-6361
VL - 685
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A14
ER -