ta2.8 – Europlanet Society

22-EPN3-019: Investigation of Ceres Bright Spots

January 23, 2024

22-EPN3-019: Investigation of Ceres Bright Spots – VIS-NIR Spectral Simulation of Haulani bright Areas by Means of Spectral Analysis on Produced Analogue Mixtures

Visit by Fabrizio Dirri and Giuseppe Massa (INAF-IAPS, Italy) to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 22 May – 03 June 2023

Report Summary: In this project different bright areas of Haulani crater (i.e. Southern floor and Central Crater Peak, named ROI3 and ROI1) on Ceres have been studied by producing different analogue mixtures starting from previous results and comparing them with Dawn VIR data. The end-members have been identified based on previous studies (Tosi et al. 2018, Dirri et al. 2022) and the analogue mixtures have been produced with grain size 50-100 µm. The two initial mixtures, i.e. SF1 and CCP_#1 have been acquired in the VIS-NIR spectral range (0.4-4.5 µm) at T environment. The Band Center, Band Depth and FWHM of absorption bands at 2.7, 3.1, 3.4 µm, spectral slope (1.2-1.9 µm range) and reflectance level at 2.1 µm of the produced SFs and CCPs mixtures have been analysed and then compared with VIR data.

The best analogues are the SF_#5 and CCP_#6 mixtures and their spectra have been acquired at low temperatures, i.e. from 190K to 230K, similar to Haulani base temperature by using Cold Spectroscopy Facility (CSS) (IPAG, France). These mixtures exhibit values for the 2.7BD (Antigorite, Illite), 3.1BD (NH4-Montmorillonite) and 3.4 BD (NaCO3) similar to Haulani ROI3 and ROI1. In particular, different dark components have been used (i.e. magnetite plus carbon black) with the aims of better reproducing the Haulani spectral slope and reflectance level. Different carbonates mix involving trona, dolomite, hydrous and anhydrous natrite have been studied to assess their contribution to 2.7 µm spectral band and the three minima at 3.33, 3.42, 3.52 µm of Haulani ROI3.

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21-EPN-FT1-003: Spectral signatures of amino acid and polypeptide embedded in water ices – Implications for biosignature identification on icy moons

June 3, 2023

21-EPN-FT1-003: Spectral signatures of amino acid and polypeptide embedded in water ices – Implications for biosignature identification on icy moons

Visit by Surendra Vikram Singh and Bhalamurugan Sivaraman, Physical Research Laboratory (India), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 23 May – 08 June 2022

Report Summary: The objective of the experiments was to obtain a spectral library of biomolecules such as amino acids in water ice in context of icy bodies of solar system. We performed a series of measurements obtaining reflectance spectra of glycine –water ice mixtures in the VIS-NIR range (0.4-4.2 μm) at the temperature range of 110-250 K and at three different concentrations, using Cold Surface Spectroscopy Facility (CSS) setup at IPAG. Glycine – water ice mixtures were studied in two different mixing modes (inter and intra mixing) to get the spectral variations due to dissolving amino acids into water. Reflectance spectra of pure glycine and pure water ice were also obtained for reference. Reflectance spectra for a shocked glycine sample (obtained from HISTA facility at PRL) was also studied to understand the effect of shock induced chemistry. These measurements will support to find the spectral signature of amino acids on icy bodies of solar system.

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21-EPN-FT1-025: Ammonium salts reflectance spectra changing viewing geometry for distinguish them on the surface of icy planetary bodies

Visit by Maximiliano Fastelli and Matteo Bisolfati, University of Perugia (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 13-25 June 2022

Report Summary: During the Europlanet 2024 RI TA Fast Track call, reflectance VIS-NIR spectra were collected at the CSS facility (IPAG) in Grenoble, France. Different viewing geometries were chosen to collect BRDF spectral data of a selected group of ammonium minerals. BRDF were collected in the 1 – 4.8 μm range considering a set of 3 incidence angles (i) (i = 0°; 30°; 60°) and 8 emergence angles (e) between -70° and 70° at room temperature. The NH4+overtone and combination bands located at ~ 1.09, 1.32, 1.62, 2.04, 2.2 and 3.05 μm are experimentally investigated.

The bands position remains unchanged varying geometrical configuration. On the other hand bands area and depth shows the highest values for i = 0° and 30° and e below 40°. These band parameters at ± 70° emergence angles evidence a decrease in their values. A general trend of spectral red shift with phase angle is observed. The bidirectional reflectance spectroscopy of selected samples shows important variations with the observation geometry of the measurements. Furthermore, from these preliminary data analyses, can be observed how reflectance values and spectral slope are affected by geometry of measurements. The surfaces of the planetary bodies are irregular and rough, which is why the effect of the observation geometry must also be considered. The collected data set can be helpful in the context of future missions aimed to understand the nature of minerals on icy and small bodies. NH4+–bearing minerals identification has a strong impact on understand their thermal evolution and the construction of geophysical internal models.

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20-EPN2-081: Vis-NIR reflection spectroscopy of ammonium salts relevant for icy planetary surface characterisation

January 6, 2022

20-EPN2-081: Vis-NIR reflection spectroscopy of ammonium salts relevant for icy planetary surface characterisation

Virtual visit by Maximiliano Fastelli, University of Perugia (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 13 October – 5 November 2021

Report Summary: During this TA visit under Europlanet 2024 RI 2nd call, reflectance VIS-NIR spectra of several ammonium salts were collected at the CSS facility (IPAG laboratory) in Grenoble, France. Different temperature steps were chosen to collect cryogenic data down to 90 K. Samples were characterised by low temperature crystalline phase transitions, and for these reasons, the measurement steps have been increased in the proximity of the expected temperature of mineral transformation. Cooling and heating experiments, using the same cooling/heating rate, were performed to bracket the phase transition T and verify its reversibility. All the spectra were collected with three different grain size (150/125 – 125/80 – 80/32 μm) in the spectral range from 1 to 4.6 μm at low T. Typical absorption features due to overtones and combinations of NH₄⁺ groups were identified in the spectral range investigated. Phase transitions, when detected, show an interesting behaviour with change in shape and position of some (sensitive) absorption bands which could be useful for the identification of these phases at non-ambient T. Moreover, the effect of low T and different granulometry were observed.

It has been proposed that ammonium minerals are present in varying percentages in icy planetary bodies. The availability of these compounds is linked to the upwelling of ammonium salts (NH₄⁺) with ice from the subsurface of possible oceans resulting from cryovolcanism phenomena. The identification of these minerals on the surface can give information about internal composition/dynamics and potential habitability of icy bodies.

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20-EPN-029: VIS-NIR reflectance analysis of analogue mixture representative of young Haulani crater on Ceres

September 5, 2021

20-EPN-029: VIS-NIR reflectance analysis of analogue mixture representative of young Haulani crater on Ceres to assess the mineralogical composition of bright areas.

Virtual visit by Fabrizio Dirri, IAPS-INAF (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 15-26 March 2021

Report Summary: In this project different bright areas of Haulani crater (e.g. Southern floor, i.e. ROI3 and North-east crater wall, i.e. ROI4) on Ceres have been studied by arranging different analogue mixtures and comparing them with Dawn VIR data. The end-members have been identified based on previous studies (Tosi et al. 2018, 2019) and the analogue mixtures have been produced with grain size 50-100µm for two bright crater regions. The two initial mixtures have been acquired in the VIS-NIR spectral range (0.35-4.5µm) at low temperature, i.e. from 200K to 300K similar to Haulani by using Cold Spectroscopy Facility (CSS) (IPAG, France).

By comparing the spectral parameters (Band Center, Band Depth and FWHM of absorption bands at 2.7, 3.1, 3.4µm, spectral slope in the 1.2-1.9µm range and reflectance level at 2.1µm) with the obtained spectra of mixtures and VIR data, the best candidate to reproduce Haulani’ bright areas is the mixture A3-8. That mixture exhibits values for the 2.7BD (Antigorite, Illite), 3.1BD (NH4-Montmorillonite), 3.4 BD (NaCO₃) and the 3.1 µm FWHM very close to Haulani ROI3 and ROI4. In order to better reproduce Haulani areas some improvements may be performed in the next future, e.g., by changing the dark component with a mixture of graphite plus magnetite to better reproduce the spectral slope of Haulani or by adding hydrous natrite in low percentage to the mixture, e.g. 2-8% to assess the role of this component found in Haulani bright areas and how is the contribution to 2.7 µm spectral band.

Read full report (published with kind permission of Dr Dirri).

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20-EPN-042: Reflectance spectroscopy of ammonium-bearing minerals

20-EPN-042: Reflectance spectroscopy of ammonium-bearing minerals – A tool to improve the knowledge of the surface of icy planetary bodies.

Virtual visit by Maximiliano Fastelli, University of Perugia (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 09-27 November 2020

Report Summary: In the frame of the Europlanet 2024 1st TA call, reflectance VIS-NIR spectra were collected. Ten different temperature steps were chosen to collect cryogenic data: 270-245-220-180-160-140-120-100-90-270 up K.

For the samples characterized by a low temperature phase transitions (mascagnite (NH₄)2SO₄, sal-ammoniac NH₄Cl, ammonium phosphate (NH₄)H₂PO₄, tschermigite (NH₄)Al(SO₄)₂·12(H₂O) and ammonium nitrate NH₄NO₃), the measurement steps have been increased in the proximity of the expected temperature of mineral transformation. Cooling and heating experiments, using the same cooling/heating rate, were performed to break the phase transition T. In particular, mascagnite, sal-amoniac and ammonium phosphate monobasic samples showed clear and very interesting spectral bands variations during cooling, indicating that a phase transition occurred. Spectra were collected with three different grain size (150/125 – 125/80 – 80/32 μm) in the spectral range from 1 to 4.8 μm.

The collected data will help on the interpretation of VIR remote spectra from Europa, Pluto’s moons, Enceladus and other icy celestial bodies surface where NH4 minerals have been supposed to occur. Moreover, the study of ammonium bearing minerals and their behavior at very low temperature might give information on how the phase transition affects the bands position and shapes inside the reflectance spectra. Overtones and combinations of NH₄ bands are in the 1-3 μm range, whereas fundamental vibrational modes (ν₁ and ν₃) are present in the ~3 μm area.

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20-EPN2-088: High spectral resolution / low-temperature IR study of carbonates

20-EPN2-088: High spectral resolution / low-temperature IR study of carbonates.

Virtual visit by Simone De Angelis and Cristian Carli, IAPS-INAF(Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 11 May – 04 June 2021

Report Summary: We planned to acquire reflectance spectra of anhydrous carbonates in the infrared range (3.2-4.6 μm), at high spectral sampling/resolution and at different cryogenic temperatures in the range 60-270K.

The analysed materials were calcite, dolomite, siderite, natrite, malachite and magnesite; all the minerals were prepared and measured at fine powders, d<50 μm. These measurements provide new spectral data in the IR that will be useful in the interpretation of remote-sensing spectroscopic observations of Solar System rocky bodies such as Mars, Jovian satellites and minor bodies by current and future missions (Mars 2020, ExoMars-2022, JUICE, Europa Clipper, OSIRIS-REx).

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