Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020
Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020

Poster presentations and abstracts

SB9

This session aims to highlight the new challenges and the missing bricks needed to understand the composition of primitive bodies through laboratory works and models.

The session focuses on the origin of inorganic and organic matter in different astrophysical environments and welcomes contributions on laboratory investigations and models of parent bodies of various meteorite groups, asteroids, comets and dwarf planets such as: a) experimental work related to the dust-regolith composition; b) observation and characterization of laboratory analogues; c) models of comet formation, and interior structure of asteroids with implications for parent body processes and evolution of small bodies in our solar system.

The session will also focus on experimental, theoretical and observational topics specifically aimed to the study organic matter in planetary bodies, including a) detection and evolution of organic compounds in the interstellar medium; b) characterization and evolution of the organic matter in the primitive bodies (meteorites, comets, IDPs); c) observation and distribution of the organic matter in the protosolar disk and planetary surfaces.

Co-organized by EXO
Convener: Gabriele Arnold | Co-conveners: Claudio Codella, John Robert Brucato, Eric Quirico, Bastian Gundlach

Session assets

Session summary

Chairperson: Eric Quirico
EPSC2020-150ECP
José L. Ramírez-Colón, José C. Aponte, Jamie E. Elsila, and Jason P. Dworkin

Abstract

The study of meteoritic organics in carbonaceous chondrites has shown how these extraterrestrial materials record valuable information about the formation of the Solar System and their potential as sources of starting materials for prebiotic organic synthesis [1]. In this study, a method for the analysis and quantification of aliphatic amides, a class of compounds that may have been precursors for other meteoritic organics, has been optimized and tested.

1. Introduction

Carbonaceous chondrites are a siliceous class of meteorites that constitute some of the most primitive extraterrestrial materials. As such, they represent a great tool to study the prebiotic chemistry of our Solar System. The chemical composition of some carbonaceous chondrites has revealed a few percents of soluble and insoluble organics including aromatic and aliphatic hydrocarbons, carboxylic acids, and amino acids among other compounds, suggesting that they could have served as vehicles for the delivery of prebiotic molecules to the early Earth [1].

Recent studies have identified aliphatic amides such as formamide as potential precursors of meteoritic and complex organics [2,3,4]. However, to date, the identification of aliphatic amides has not been reported in meteorites. Here, we present the results of our method development for the identification and quantification of meteoritic aliphatic amides.

2. Derivatization Testing

Silylation derivatization of amides increases their thermal stability and facilitates their analysis by gas chromatography-mass spectrometry (GC-QqQMS). We tested the silylation of eleven aliphatic amides and urea (Figure 1) using N-methyl-trimethylsilyl trifluoroacetamide (MSTFA). We also tested other three silylation reagents: N,N-diethyltrimethylsilylamine (TMSDEA), N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA + TMCS, 99:1), and N-tert-butyldimethylsilyl-N-methyltrifluoroacet-amide (MTBSTFA), at different temperatures, reaction times, solvents, volume of solvents, and catalytic conditions (using acids or bases; e.g., hydrochloric acid, boron trifluoride, pyridine, triethylamine, trimethylamine, etc.). The derivatization of the aliphatic amides with MSTFA resulted in the highest yields, the shortest derivatization times, and the best derivative stability.

To evaluate the effects of likely meteoritic minerals on extraction and derivatization of the amides, pyrolyzed Allende meteorite powder was impregnated with amide standards and taken through our optimized method. No decomposition of the amides and no significant byproduct formation was observed due to the influence of minerals (Figure 1).

3. Meteorite Results

We extracted 200 mg of the Murchison meteorite in anhydrous dichloromethane/acetonitrile and evaluated for aliphatic amides after MSTFA derivatization. From our analysis (Figure 1), we observed a tentative detection of meteoritic acetamide, however, this detection may be a byproduct of the extraction and silylation derivatization. It is possible that no acetamide is present in Murchison (or present below our detection limits), as we believe that at least a portion of the acetamide we found in our Murchison meteorite sample may have resulted from the partial hydrolysis of the acetonitrile either during meteorite extraction or during extract derivatization.

Additional studies to understand the effects of water during extraction and derivatization of aliphatic amides are needed. Future experiments may involve the use of Allende pyrolyzed powder impregnated with trace amounts of water in the absence and presence of aliphatic amide standards. Additionally, to absorb water in the medium during extraction and derivatization, we may test (i) molecular sieves or celite, and (ii) drying agents such as anhydrous salts.

Figure 1. GC-MS chromatograms of MSTFA-amide derivatives in standard mixture, procedural blank, standard mixture + 200mg of pyrolyzed Allende, and 200mg of Murchison extracted in dichloromethane/acetonitrile (7:3). Peak ID: 1, formamide; 2, acetamide; 3, N-methylformamide; 4, N-methylacetamide; 5, N-ethylformamide; 6, propanamide; 7, isobutyramide; 8, trimethylacetamide; 9, butanamide; 10, pentanamide; 11, urea; 12, hexanamide.

4. Conclusions

Based on the possibility that aliphatic amides could serve as possible precursors to the prebiotic chemistry of early Earth, this study evaluated and developed a derivatization technique for the analysis of this compound class in carbonaceous chondrites. The low levels of organic content and the high molecular complexity of carbonaceous chondrites make method development targeting specific compound classes a challenging and lengthy process [5]. Further optimization of this protocol is needed before applying it to carbonaceous chondrites of different petrological types.

Acknowledgments

This research was supported by the Goddard Center for Astrobiology, and a grant from the Simons Foundation (SCOL award 302497 to J.P.D.).

References

[1] Glavin D. P., Alexander C., Aponte J. C., Dworkin J. P., Elsila J. E., and Yabuta H.: The Origin and Evolution of Organic Matter in Carboneceous Chondrites and Links to Their Parent Bodies, Primitive Meteorites and Asteroids, Amsterdam, Netherlands: 205-271, 2018.

[2] Saladino R., Botta G., Pino S., Costanzo G., and Di Mauro, E.: From the one-carbon amide formamide to RNA all the steps are prebiotically possible, Biochimie, 94, 1451-1456, 2012.

[3] Saladino R., Carota E., Botta G., Kapralov M., Timoshensko G., Rozanov A. Y., Krasavin E., and Di Mauro E.: Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation, PNAS, 112, 21: E2746-E2755, 2015.

[4] Costanzo G., Saladino R., Crestini C., Ciciriello F., and Di Mauro E.: Formamide as the main building block in the origin of nucleic acids, BMC Evol. Biol., 7, S1, 2007.

[5] Simkus D. N., Aponte J. C., Elsila J. E., Parker E. T., Glavin D. P., and Dworkin J. P.: Methodologies for analyzing soluble organic compounds in extraterrestrial samples: Amino acids, amines, monocarboxylic acids, aldehydes, and ketones, Life, 9, 47, 2019.



 

How to cite: Ramírez-Colón, J. L., Aponte, J. C., Elsila, J. E., and Dworkin, J. P.: Towards and Effective Method for the Analysis of Meteoritic Amides, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-150, https://doi.org/10.5194/epsc2020-150, 2020.

EPSC2020-187
Paola Manzari, Gioacchino Tempesta, Daniela Mele, and Giovanna Agrosì

Among the cutting-edge techniques that are being using in the meteoritics discipline to explore potential new properties, the micro-CT is useful in its potential of showing phase distribution in a 3D reconstruction and analyses of a small meteorite volume and in showing microstructures, crystal habits or grains, occurrences of vesicles or voids, melt veins and fractures. In this view, we studied a sample of Al Haggounia, a meteorite significantly porous with pore sizes from several cm to hundreds of microns. This meteorite after a complex history of classification results to be an EL-impact melt. The fragments show very different looking, from the point of view of microstructure of impact shock:  melt veins, fractures and pores and, consequently, this meteorite is particularly suitable for investigations by micro-CT coupling with SEM-EDS analyses to fit the chemical data to the textural ones. All the data obtained help us in the genetic interpretation allowing to verify the hypothesis about the origin of this meteorite developed until now.

How to cite: Manzari, P., Tempesta, G., Mele, D., and Agrosì, G.: Studying the fossil meteorite Al Haggounia by X-ray Micro-CT, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-187, https://doi.org/10.5194/epsc2020-187, 2020.

EPSC2020-828ECP
César Feniou, Lora Jovanovic, Thomas Gautier, Nathalie Carrasco, Jérémy Bourgalais, Philippe Boduch, Hermann Rothard, Basile Augé, Bernard Schmitt, Marie Fayolle, Véronique Vuitton, Olivier Poch, and Eric Quirico

I. Introduction

On Pluto, the largest object in the Kuiper Belt, the dark surface of Cthulhu seems to indicate the presence of photochemical aerosols, stemming from the interaction between solar ultraviolet radiation and atmospheric methane, nitrogen, carbon monoxide, and further sedimentation [1-4]. Tholins have been tested and identified as analogues of the said surface. The flyby of the New Horizons Pluto probe enabled reflectance spectra acquisitions of the Cthulhu region. Dissimilarities were found with the reflectance of Pluto tholins, which might be due to Galactic Cosmic Rays (GCR) irradiation of Pluto’s surface [5]. To test this hypothesis, Pluto tholins were synthesized and swift heavy ion irradiation was performed on the analogues to simulate the impact of cosmic rays on the surface of Cthulhu region. Moreover, GCR-analogues irradiation of the said tholins triggers a desorption of organic volatile compounds whose study could provide crucial information on both the structure of tholins and the chemical mechanisms involved. The volatile desorption was followed by mass spectrometry.

II. Methods

The tholins samples were produced within the PAMPRE experiment (LATMOS, France) using a N2:CH4 (99:1) and CO (500 ppm) gaseous mixture submitted to a plasma discharge [6]. The operating conditions were 0.9 ± 0.1 mbar total pressure and ambient temperature. The tholins samples were deposited as thin film onto a polished MgF2 substrate.

The irradiation experiments were performed at the heavy ion accelerator GANIL (Caen, France) using the IGLIAS experimental setup [7] at ambient temperature with a beam flux of 109 Xe ions cm−2 s−1. Mass spectrometry measurements were performed using a quadrupole mass-spectrometer operating with electron ionization (EI) at 70 eV and a scan range from m/z 1 to 100 before and during the irradiation. Mass spectrometry was normalized to the signal of water (m/z 18) because it is the most intense peak and it is not affected by the irradiation. The error bars represent Type B uncertainties relating to measurement.

A Monte-Carlo approach [8] was used to decompose the mass spectrum. Fragmentation data under EI 70 eV of 118 molecules were collected from the NIST Chemistry WebBook. The database was then narrowed by removing the molecules whose parent peak does not coincide with a signal on the experimental spectrum. The Monte-Carlo algorithm then managed to fit the fragmentation patterns of the dabatase compounds with the experimental spectrum. The deconvolution was performed 100,000 times to obtain a statistical distribution and the calculation uncertainties were plotted.

III. Results

The mass spectrometry analysis (Fig. 1) shows a notable increase in intensity for many peaks of the C1 and C2 groups under irradiation. For higher m/z, most peaks only appear at a significant intensity when the tholins are irradiated. No signal was detected over m/z 53 in either experiment.

The deconvolution (Fig. 2) permitted identification of the volatiles released. First, we report a clear increase in desorption of nitriles and unsaturated hydrocarbons under heavy ion irradiation. When the tholins were irradiated, hydrogen cyanide production was 20 times higher and it is observed that cyanogen and propiolonitrile formation and fragmentation shaped the significant C4-group signals (m/z 50, 51, 52). Allene and acetylene production also appeared under irradiation. Second, the Monte-Carlo calculation did not manage to fit the database’s compounds to the experimental results for m/z 12, 26, 29, 36, 38. These signals are thought to be fragments from secondary reactions, fragments being C+, CN+, N2H+, C3+, C2N+ respectively [9,10], but may also be fragments of a molecule from outside our database. For instance, methanimine (m/z 29) is a credible candidate [11] but no EI fragmentation data is available.

IV. Discussion and conclusion

The interaction of cosmic rays’ analogues with N2-rich ices inside icy bodies in the outer Solar System already shown a production of a few different species (HCN, CN, NH3…) [12-14]. The identification of the desorbed species has shown that the chemical families of volatiles follow a similar trend under pyrolysis [15]. Herein, we reported that GCRs are likely to create diversity in desorbed volatiles from the organic surface of Pluto. Consequently, the atmosphere might contain new molecules. Their abundance is however a pending issue, and the determination of the production yield of these new species requires further investigation of the experimental data. Investigations are ongoing to test if the modifications induced by the GCRs could explain the optical differences found between the organic deposits observed on Pluto and the tholins produced in the laboratory.

References

[1] Stern S. A. et al., Science, Vol. 350, aad1815, 2015.
[2] Gladstone G. R. et al., Science, Vol. 351, aad8866, 2016.
[3] Grundy W. M. et al., Icarus, Vol. 314, pp. 232-245, 2018.
[4] Cruikshank D. P. et al., Icarus, Vol. 246, pp. 82-92, 2015.
[5] Fayolle M. et al., EPSC-DPS 2019, Testing tholins as analogs of the dark reddish material covering the Cthulhu region
[6] Szopa C. et al., Planetary and Space Science, Vol. 54, pp. 394-404, 2006.
[7] Augé B. et al., Review of Scientific Instruments, Vol. 89, 075105, 2018.
[8] Gautier T. et al., Rapid Communications in Mass Spectrometry, 2019.
[9] Bohme D. K. et al., Mass Spectrom. Ion Processes, Vol. 81, pp. 123-145, 1987.
[10] Carrasco N. et al., Icarus, Vol. 2019, pp. 230–240, 2012.
[11] Bourgalais J. et al., JGR Space Physics, 2019, 10.1029/2019JA026953.
[12] Augé B. et al., Astronomy & Astrophysics, 592, A99, 2016.
[13] Vasconcelos F. A. et al., Phys. Chem. Chem. Phys, 19, 1284, 2017.
[14] Vasconcelos F. A. et al., Phys. Chem. Chem. Phys, 19(35), 24154–24165, 2017.
[15] He J. et al., Icarus, Vol. 248, pp. 205–212, 2015.

How to cite: Feniou, C., Jovanovic, L., Gautier, T., Carrasco, N., Bourgalais, J., Boduch, P., Rothard, H., Augé, B., Schmitt, B., Fayolle, M., Vuitton, V., Poch, O., and Quirico, E.: Simulated effect of the Galactic Cosmic Rays on the surface of Pluto’s dark-red region, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-828, https://doi.org/10.5194/epsc2020-828, 2020.

EPSC2020-945
Peter Sarre

Dust particles play a major role in the formation, evolution and chemistry of interstellar clouds, stars, and planetary systems. Commonly identified forms include amorphous and crystalline carbon-rich particles and silicates. Also present in many astrophysical environments are polycyclic aromatic hydrocarbons (PAHs), detected through their infrared emission, and which are essentially small flakes of graphene. Astronomical observations over the past four decades have revealed a widespread unassigned ‘extended red emission’ (ERE) feature which is attributed to luminescence of dust grains. A luminescence feature with similar characteristics to ERE has been found in organic material in interplanetary dust particles and carbonaceous chondrites.  

There is a strong similarity between laboratory optical emission spectra of graphene oxide (GO) and ERE, leading to this proposal that emission from GO nanoparticles is the origin of ERE and that heteroatom-containing PAH structures are a significant component of interstellar dust. The proposal is supported by infrared emission features detected by the Infrared Space Observatory (ISO) and the Spitzer Space Telescope.  

Insoluble Organic Material (IOM) has a chemical structure with some similarities to graphene oxide.  It is suggested this may contribute to the discussion as to whether IOM has an origin in the interstellar medium or the solar nebula, or some combination.

How to cite: Sarre, P.: ERE from Graphene Oxide in the ISM. A possible link to IOM? , Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-945, https://doi.org/10.5194/epsc2020-945, 2020.

EPSC2020-1006ECP
Arijit Roy, Vikram Surendra, Mallaya Ambresh, Jaykrishna Meka, Jayaram Vishakantaiah, Vijayanand Chandrasekaran, Anil Bhardwaj, Nigel J Mason, and Bhalamurugan Sivaraman

Owing to the importance of complex molecules in the Interstellar Medium (ISM), many experiments have been carried out to understand their synthesis in interstellar conditions. Amongst the complex molecules identified Polyaromatic hydrocarbons (PAH) and structured carbon, such as C60/C70, have attracted alot of interest due to their characteristic absorption/emission in the infrared which is believed to explain many of the infrared bands in the ISM [1]. In addition to the PAHs, Mixed Aromatic / Aliphatic Nanoparticles (MAONs) are also proposed to contribute to the spectral signatures that are observed in the ISM [2]. 


The synthesis of such complex molecules is either via the energetic processing of simple hydrocarbon molecules, a simple bottom-top model, or via a complex route where PAH molecules are synthesized on a graphitized silicon carbide surface, a top-bottom chemical pathway [3]. In the top-bottom model, energetic processing of graphene has been shown to synthesize fullerene (C60) [4] whilst UV processing of arophatic molecules has been shown to synthesize C60 [5]. Another route is irradiation of the icy mantles of interstellar dust for example simple hydrocarbons such as methane subjected to irradiation in a Neon matrix have been observed to synthesize carbon clusters up to C20 [6].  

Therefore, there is clearly a demand for more experiments to understand the end products resulting from carbon as the starting material. We employed the high intensity shock tube in PRL to shock the pure (<100 nm) carbon powder to temperatures as high as 8000 K for about 2 ms. The resulting sample after shock processing was analysed using Raman, IR spectroscopy and Imaging (FE-SEM / HR-TEM) techniques. Here we present the first results from the preliminary experiments carried out by shock processing carbon nanopowder.

References           

  • [1] Cami J., Bernard-Salas J., Peeters E. & Malek S. E., Detection of C60 and C70 in a Young PlanetaryNebula, (2010), Science, 329, 1180-1182.
  • [2] Kwok S. & Zhang Y., Mixed aromatic–aliphatic organic nanoparticles as carriers of unidentifiedinfrared emission features, (2011), Nature, 479, 80-83.
  • [3] Merino P. et al. Graphene etching on SiC grains as a path to interstellar polycyclic aromatichydrocarbons formation, (2014) Nature Communications, 5, 3054.
  • [4] Berné O. & Tielens A. G. G. M., Formation of buckminsterfullerene (C60) in interstellar space, (2012) Proceedings of the National Academy of Sciences, 109, 401.
  • [5] Elisabetta, R. M. et al. The Formation of Cosmic Fullerenes from Arophatic Clusters, (2012), TheAstrophysical Journal, 761, 35.

        [6] Lin M.-Y. et al., Vacuum-Ultraviolet Photolysis of Methane at 3 K: Synthesis of Carbon Clusters upto C20, (2014), The Journal of Physical        Chemistry A, 118, 3438-3449.              

How to cite: Roy, A., Surendra, V., Ambresh, M., Meka, J., Vishakantaiah, J., Chandrasekaran, V., Bhardwaj, A., Mason, N. J., and Sivaraman, B.: Shock processing of carbon nanopowder , Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-1006, https://doi.org/10.5194/epsc2020-1006, 2020.

EPSC2020-318ECP
Stefano Pantaleone, Matteo Signorile, Nadia Balucani, Francesca Bonino, Gianmario Martra, and Piero Ugliengo

Formamide has been recognized in the literature as a key species in the formation of the complex molecules of life, such as nucleobases. Furthermore, several studies reported the impact of mineral phases as catalysts for its decomposition/polymerization processes, increasing the conversion and also favoring the formation of specific products. Despite the progresses in the field, in situ studies on these mineral-catalyzed processes are missing. In situ UV-Raman characterization of the chemical evolution of formamide over amorphous SiO2 samples, selected as a prototype of silicate minerals, was performed. The experiments were carried out after reaction of formamide at 160 °C on amorphous SiO2 (Aerosil OX50) either pristine or pre-calcined at 450 °C, to remove a large fraction of surface silanol groups. Our measurements, interpreted on the basis of density functional B3LYP-D3 calculations (Figure 1), allow to assign the spectra bands in terms of specific complex organic molecules, namely, diaminomaleonitrile (DAMN), 5-aminoimidazole (AI), and purine, showing the role of the mineral surface on the formation of relevant prebiotic molecules.

How to cite: Pantaleone, S., Signorile, M., Balucani, N., Bonino, F., Martra, G., and Ugliengo, P.: Monitoring the Reactivity of Formamide on Amorphous SiO2 by In-Situ UV-Raman Spectroscopy and DFT Modeling, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-318, https://doi.org/10.5194/epsc2020-318, 2020.

EPSC2020-753ECP
Clement Feller, Antoine Pommerol, and Bastian Gundlach and the CoPhyLab Team

Abstract:
Even as the late space exploration ESA/ROSETTA mission allowed to perform the most complete investigation of a cometary nucleus to date [1], and observations of interstellar comet 2I/Borisov hint to the pervasiveness of typical cometary properties beyond our solar system [2], our understanding of underlying physical processes occurring on surfaces of cometary nuclei remains limited.
Based on the present advances in cometary sciences, the Cometary Physics Laboratory project (hereafter CoPhyLab) is performing series of laboratory measurements and sublimation experiments to investigate thoroughly and shed further lights on these processes.
We report on the present status of photometric and spectrophotometric measurements of minerals and organics compounds mixtures at the Bern University in view of the next rounds of CoPhyLab experiments.

Introduction:
Icy small bodies of the solar system are remnants of the swarm of planetesimals that populated the protoplanetary disk, 4.57 Gyrs ago. Confined in the thermally and dynamically cold outer reaches of the system, their composition and other physical properties are a tracer for the formation and evolution processes of the solar system.
The successive space missions to cometary nuclei have gathered troves of detailled measurements and allowed a glimpse on the complexity and variability of their properties [3,4]. Extensive campaigns of comprehensive laboratory experiments are being prepared as part of the CoPhyLab project [5] in order to further unravel the physical processes cometary material experience.
As part of the CoPhyLab experiments, we are currently investigating the optical properties of mineral and organic materials (e.g. graphite, humic acid and SiO2) using photometric and spectrophotometric measurements made at the Bern University.

Instruments and samples:
The Ice Laboratory of the Bern University has developed over the years a collection of instruments dedicated to the characterization of the physical properties of minerals, simple organic compounds and ices, with a particular expertise in the production of water ices [6].
The present investigations are focused on the characterization of the optical properties of a assortment of graphite, humic acid and SiO2 mixtures. These mixtures will be used in a subsequent time in sublimation experiments, as the “dust”-part of an analogue to the observed physical properties of the cometary surface materials [7]. The photometric and spectrophotometric measurements of these investigations are made with the PHIRE-2 goniometer and the MoHIS spectro-imager.

The PHIRE-2 acquires the bidirectional reflectance (hereafter BRDF) of samples across the whole hemisphere [8]. A monochromatic 250 W halogen lamp and 6 broadband filters are used to provide illumination in the visible and near-infrared domain (430-1070 nm). Light is then conveyed through an optical fibre up to the incidence arm of the goniometer, at the end of which a set of mirror, iris and lens focus the beam on the sample. The light reflected by the illuminated surface is integrated by a 1-pixel silicium detector affixed at the end of the emergence arm. The emergence arm can be equipped either with a beam-splitter setup or a 45° slanted mirror, thus allowing to investigate the sample’s phase function between 10-3 ° and 5° and from 4° to 180° of phase angle. As the sample is installed on a rotating holder, it is thus possible to measure its BRDF across the whole hemisphere.

The MoHIS spectro-imager allows to map the spectral reflectance across samples’ surfaces from 300 nm to 2500 nm, using a visible camera (a 1392x1040 pixels CCD detector, with an average image scale of 0.46 mrad.pxl-1) and an infrared camera (a 320x256 pixels MCT detector, with an average image scale of 2.25 mrad.pxl-1). Another halogen lamp and a gratings monochromator coupled to a 5 mm-diameter fibre bundle provide illumination of the samples’ surfaces with adjustable wavelength bandpasses (as narrow as 5 nm).

The samples investigated are mixtures of synthetic graphite (CAS: 7782-42-5), humic acid (CAS: 1415-93-6) and SiO2 (CAS:14808-60-7). The current CoPhyLab investigations are performed on a set of 10 mixtures with respective mass fractions of : 33%; (40%, 30%, 30%); (60%, 20%, 20%) and (80%, 10%, 10%), not including measurements performed on each unmixed component.
Further considerations on these mixtures shall be discussed by [9].

Data modelling:
Once acquired, the complete dataset of BRDFs of pure components and mixtures shall be modelled using the semi-empirical Hapke photometric model [10].
This modelling is done using both an elementary implementation of the Hapke model, as well as an implementation including a surface roughness correction [11], a porosity correction [12], and additional modifications discussed in [13,14]. This later implementation of the model was used previously to model the BRDF of comet 67P/ Churyumov-Gerasimenko [15].

Perspectives:
The CoPhyLab project is presently investigating the properties of minerals and organics mixtures to produce an material matching measured physical properties of cometary nuclei’ surfaces, in view of upcoming sublimation experiments with the CoPhyLab sublimation chamber.
The measurements of the bidirectional reflectance and reflectance spectra of these mixtures are on-going and the results of these investigations will be presented.

References:
[1] Taylor et al., 2017, PTRSA, 375, 2097, DOI: 10.1098/rsta.2016.0262
[2] Bolin et al., 2020, AJ, 160, 1, DOI: 10.3847/1538-3881/ab9305
[3] A'Hearn, 2011, ARAA, 49, 281 DOI: 10.1146/annurev-astro-081710-1025
[4] Rubin et al., 2019, MNRAS, 489, 1, DOI: 10.1093/mnras/stz2086
[5] Kreuzig et al., In prep, The CoPhyLab Comet Simulation Chamber
[6] Pommerol et al., 2019, SSRv, DOI: 10.1007/s11214-019-0603-0
[7] Gundlach et al., 2020, this EPSC
[8] Pommerol et al., 2011, PSS, DOI: 10.1016/j.pss.2011.07.009
[9] Lethuillier et al., 2020, this EPSC
[10] Hapke, 1993, Cambridge University Press, 978-0-521-88349-8
[11] Hapke, 1984, Icarus, 59, 41-59, DOI: 10.1016/0019-1035(84)90054-X
[12] Hapke, 2008, Icarus, 195, 918-926, DOI: 10.1016/j.icarus.2008.01.003
[13] Helfenstein et al., 2011, Icarus, 215, 83-100, DOI: 10.1016/j.icarus.2011.07.002
[14] Shkuratov et al., 2012, JQRST, 113, 2431-2456, DOI: 10.1016/j.jqsrt.2012.04.010
[15] Feller et al., 2016, MNRAS, 462, 5287-5303, DOI: 2016MNRAS.462S.287F

How to cite: Feller, C., Pommerol, A., and Gundlach, B. and the CoPhyLab Team: Photometric and spectrophotometric measurements of the CoPhyLab dust mixtures., Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-753, https://doi.org/10.5194/epsc2020-753, 2020.

EPSC2020-847ECP
Robin Sultana, Pierre Beck, Olivier Poch, Bernard Schmitt, Alessandro Maturilli, Giulia Alemanno, and Joern Helbert

Introduction
Small bodies of the Solar System are residues of the epoch of formation of the planetary system. The most primitive of these bodies are likely comets, that should provide the best recording of the chemical composition and mineralogy of the protoplanetary disk. P- and D-type asteroids present featureless reddish spectra similar to the comets nuclei ([10]; [8]) and are believed to be somehow related to comets. Mid-infrared spectroscopic observations have led to the suggestion that these objects are covered by a porous layer constituted of submicrometer-sized (hyperfine) grains ([2]; [11]).
Radiative transfer models have been used to retrieve composition from cometary dust emission as well as asteroid mid-IR spectra ([3]; [4]), but laboratory simulations on specific analogues that could also give indication regarding their compositionand their surface texture (porosity, roughness) are currently lacking. This study aims to explore the emission spectral features of hyperfine and hyperporous powders with decreasing grain size in order to compare laboratory simulations to observational data of the comet C/1995 Hale-Bopp and the D-type Trojan asteroid (624) Hektor.


Methods
Using a specific grinding and sieving protocol [9] we were able to produce large quantities of powder of different composition (olivine and smectite) at decreasing grain size. Grain size has been quantified using SEM imaging. The finest powders obtained have average grain size below one micron.
In order to explore the effect of porosity on emission spectra, we produced hyperporous surfaces (with a porosity larger than 99 %) by sublimating under vacuum mixtures of water ice particles containing the mineral powders, following the protocol described in [7]. We also simulated porosity in our samples by mixing the mineral powders (1 vol%) with potassium bromide (KBr, 99 vol%), which is non-absorbing in the Vis-IR.
The powders were brought to the DLR in Berlin to perform emissivity measurements at the PSL [5]. During the measurements, samples are heated from the bottom of the sample holder. Measurements at several temperatures were obtained. Emission spectra in the mid-infrared region were measured on the different samples.
 Reflectance was measured after direct emissivity measurements to observe chemical/mineralogical changes during the heating process.
 
Results
Figure 1 presents normalized emissivity spectra between 8 and 13 µm of the hyperfine powder of olivine, the hyperporous and hyperfine smectite powder, the KBr-diluted olivine powder, and observations of D-type asteroid Hektor and comet Hale-Bopp ([2]; [1]).
                                                                                                    
Both observations of Hektor and comet Hale-Bopp exhibit a notable emission feature in the region 9-12 µm.
 Powder of submicroscopic olivine does not show the silicates emission features around 10 µm as well as the hyperporous smectite sample. These two spectra are very flat on the whole spectral range studied here.
 The spectrum of the KBr-diluted powder however shows a strong feature around 10 µm.

Discussion
Emissivity of D-type objects resembles to features observed for cometary dust tails ([2]; [10]). This may seem surprising at first since cometary dust tail may not be optical thick, while the surface of an asteroid is. The presence of such an emissivity feature has been interpreted by the presence of high-porosity, based on reflectance measurement of mixture of silicates with KBr.
In the present work, we produced a hyperporous and hyperfine grained sample to simulate the presence of porosity without using KBr, which showed that such sample is featureless and has an emissivity close to 1 (whether emissivity is directly measured or estimated by Kirchoff's law). This means that porosity solely cannot explain the presence of emissivity features of silicates on small bodies. Emissivity of samples with porosity simulated using KBr and with real porosity are therefore very different in our results. This could be explained by the fact that, while KBr is non-absorbing, its real optical index is higher than 1. Using KBr will increase reflectance outside of where the silicate absorbs and therefore decrease emissivity, thereby producing the observed emission contrast. So alternative processes have to be proposed to explain the presence of emission feature.
A first one is that, somehow similar to KBr, a brightening constituent is present in the material of D-type asteroids. Potential candidates are salts, responsible for the 3.2 µm signature on comet 67P/Churyumov-Gerasimenko and possibly on some asteroids including Trojans [6]. Another possibility that needs to be investigated is the presence of a temperature gradient. In our experiment the temperature at the top of the sample is lower than at the bottom, and there is no emissivity feature in the measured spectra. However, when observing the illuminated side of an object, the temperature gradient is in the other direction (the top surface is warmer). If only a few layers of hot surface grains are producing the emission signature, they may emit like an optically thin layer, similarly to cometary dust tails. The two possiblities will be investigated further.
 
Acknowledgements
This work was funded by the European Research Council under the SOLARYS grant agreement ERC-CoG2017-771691. Visit to DLR was supported by the Europlanet 2020 RI Program (H2020), grant N° 654208.
 
References
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[2] Emery, J.  et al., 2006.  Icarus, 182(2):496 – 512. Results from the Mars Express ASPERA-3 Investigation.
[3] Gicquel, A. et al., (2012). Astronomy & Astrophysics, 542:A119.
[4] Licandro, J., et al., (2011). Astronomy and Astrophysics, 525(13):1–7.
[5] Maturilli, A. et al., (2019). The newly improved set-up at the Planetary Spectroscopy Laboratory (PSL).
[6] Poch, O. et al., (2020). Science, 367 (6483).
[7] Poch, O. (2016). Icarus, 267:154–173.
[8] Raponi, A. et al., (2020). Nature Astronomy, 4:500–505.
[9] Rousseau, B. et al., (2018). Icarus, 306:306–318.
[10] Vernazza, P. and Beck, P. (2016). Composition of Solar System small bodies.
[11] Vernazza, P. et al., (2012). Icarus, 221(2):1162–1172.

How to cite: Sultana, R., Beck, P., Poch, O., Schmitt, B., Maturilli, A., Alemanno, G., and Helbert, J.: Mid-IR emissivity of hyperfine small bodies analogues, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-847, https://doi.org/10.5194/epsc2020-847, 2020.

EPSC2020-250
Jörn Helbert, Enrica Bonato, and Alessandro Maturilli

Introduction:  Building on the available infrastructure and the long heritage in spectral studies of planetary (analog) materials DLR is creating a Sample Analysis Laboratory (SAL). The setup has started with the installation of a vis-IR-microscope at the Planetary Spectroscopy Laboratory in 2018. Full funding has been approved in December 2019.

SAL will add over the next 3 years capabilities for detailed mineralogical and geochemical characterization of material return by sample return missions in a clean room facility. The step-wise extension follows the successful development approach used for the Planetary Spectroscopy Laboratory (PSL) and Astrobiology Laboratories. The goal is to test and validate each extension step before planning the follow-up step. The first step is focused on analysing samples from asteroids missions like Hayabusa 2 mission, Osiris-REX and lunar sample return missions. SAL can later be extended to a full Sample Curation facility.

Global reconnaissance of planetary surface can only be obtained by remote sensing methods. Optical spectroscopy from UV to far-infrared is playing a key role to determine surface mineralogy, texture, weathering processes, volatile abundances etc. It is a very versatile technique, which will continue to be of importance for many years to come. Providing ground truth by in-situ measurements and ultimately sample return can significantly enhanced the scientific return of the global remote sensing data. This motivates the planned extension of PSL with a SAL by support of the Astrobiology Laboratories.

SAL will focus on spectroscopy on the microscopic scale and geochemical and geo-microbiological analysis methods to study elemental composition and isotopic ratios in addition to mineralogy to derive information on the formation and evolution of planetary surfaces, search for traces of organic materials or even traces of extinct or extant life and inclusions of water.

The DLR SAL will be operated as a community facility (much like PSL), supporting the larger German and European sample analysis community

Current facilities: PSL at DLR (http://s.dlr.de/2siu) is the only spectroscopic infrastructure in the world with the capability to measure emissivity of powder materials, in air or in vacuum, from low to very high temperatures, over an extended spectral range. Emissivity measurements are complimented by reflectance and transmittance measurements produced simultaneously with the same setup. It is the ground reference laboratory for the MERTIS thermal infrared spectral imager on the ESA BepiColombo mission. Members of the PSL group are team members of the MarsExpress, VenusExpress, MESSENGER and JAXA Hayabusa 2 missions. For the latter mission PSL has performed ground calibration measurements. In addition PSL has been used extensively in support of the ESA Rosetta mission. The samples analyzed at PSL ranged from rocks, minerals, to meteorites and Apollo lunar soil samples.

In a climate-controlled environment PSL operates currently two Fourier Transform Infrared Spectrometer (FTIR) vacuum spectrometers, equipped with internal and external chambers, to measure emittance, transmittance and reflectance of powdered or solid samples in the wavelength range from 0.3 to beyond 100 micron. Recently a Hyperion 2000 microscope has been added in preparation of the SAL setup.

The institute is also operating a Raman micro-spectrometer lab (http://s.dlr.de/e49q) with a spot size on the sample in focus of <1.5 µm. The spectrometer is equipped with a cryostat serving as a planetary simulation chamber which permits simulation of environmental conditions on icy moons and planetary surfaces, namely pressure (10-6 hPa  – 1000 hPa), atmospheric constituents, and temperature (4K – 500K). The samples, which are analyzed in the laboratory range from minerals, Martian analog materials, meteorites, biological samples (e.g. pigments, cell wall molecules, lichens, bacteria, archaea and other) to samples returned from the ISS (BIOMEX) and the asteroid Itokawa (Hayabusa sample).

All laboratory facilities undergo regular evaluations as part of the DLR quality management process. The evaluations address laboratory protocols, documentation, safety, data archival and staff training.

PSL is a community facility as part of the “Distribute Planetary Simulation Facility” in European Union funded EuroPlanet Research Infrastructure (http://www.europlanet-2020-ri.eu/). Through this program (and its predecessor) over the last 7 years more than 60 external scientists have obtained time to use the PSL facilities. PSL has setup all necessary protocols to support visiting scientist, help with sample preparation, and archive the obtained data.

Sample Analysis Laboratory:  The near-term goal of the first step is the preparation to receive samples from the JAXA Hayabusa 2 and MMX missions, the Chinese Chang-E 5 and 6 missions as well as the NASA Osiris-REX mission. The current PSL and Raman facilities are operating in climate-controlled rooms and follow well-established cleanliness standards. The SAL will be housed in two ISO 5 clean rooms. The cleanrooms are equipped with glove boxes to handle and prepare samples. All samples will be stored under dry nitrogen and can be transported between the instruments in dry nitrogen filled containers.

To characterize and analysis the returned samples the existing analytical capabilities are currently been extended. PSL was just upgraded with a vis-IR-microscope to extend spectral analysis to the sub-micron scale.

For the SAL this will be complemented by the following capabilities:

Based on current planning the first parts of SAL will be operational and ready for certification by end of 2021. Analysis of first Hayabusa 2 samples can start by beginning to mid of 2022.

Outlook: DLR has started establishing a Sample Analysis Laboratory. Following the approach of a distributed European sample analysis and curation facility as discussed in the preliminary recommendations of EuroCares (http://www.euro-cares.eu/) the facility at DLR could be expanded to a curation facility. The timeline for this extension will be based on the planning of sample return missions. The details will depend on the nature of the returned samples. Through the BIOMEX project a collaboration has been established with the Robert-Koch Institute (RKI) (http://www.rki.de) for question of samples that might pose a bio-hazard. RKI is operating BSL 4 facilities, which might be used as part of the DLR curation facilities.

How to cite: Helbert, J., Bonato, E., and Maturilli, A.: Planetary Sample Analysis Laboratory (SAL) at DLR , Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-250, https://doi.org/10.5194/epsc2020-250, 2020.

EPSC2020-1109ECP
Georgios Tsirvoulis and Mikael Granvik

The study of Near Earth Objects has gathered significant scientific interest over the past few decades. Although the primary drive for this research is the need to discover and quantify potential threats to Earth, we have also gained substantial information about the formation and evolution of the Solar System, regarding both dynamical and physical processes.
One such process, by which asteroids that approach very close to the Sun are disintegrated, has been proposed by the most recent population models of NEOs to match the observational data. Our aim is to understand these physical processes therefore we are building an experimental apparatus which will enable us to simulate the extreme conditions of the Solar neighborhood.
The experimental setup will consist of a vacuum chamber, wherein asteroid simulant samples will be placed. To simulate the Solar radiation we will make use of a high power Xenon lamp able to deliver a beam of about 50 W/cm2 of maximum power on the sample. To expand the parameter space we will use a periodic shutter to emulate the rotation of the asteroid, and a power attenuator to probe different heliocentric distances. The process will be monitored by regular and high-speed cameras in order to record and study the production and velocities of ejecta. Thermocouples will also be used to log the temperature changes of the samples, and a mass spectrometer fitted on the chamber will enable us to determine the composition of the reaction products.
Apart from our main goal, which is to study the disruption of NEOs close to the Sun, we believe that the capabilities of our experimental setup extend beyond that. We believe it could offer an opportunity for a number of different experiments, such as tests of spacecraft composites or alloys, and we welcome collaborations to work on new ideas.

How to cite: Tsirvoulis, G. and Granvik, M.: Space simulator of the near-Sun environment, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-1109, https://doi.org/10.5194/epsc2020-1109, 2020.