ERIM is a new kind of meeting to support European planetary science and associated communities. The format of ERIM 2023 is a series of interactive workshops related to the activities of the Europlanet 2024 Research Infrastructure (RI) project, research infrastructures in general, and the Europlanet Society. The meeting will be co-hosted with EPEC Annual Week 2023, the training school for the Europlanet Early Career Network.
How will it Work?
Workshops will be organised under a series of programme tracks. You can dip in and out of programme tracks, workshops and even sessions during the week. The aim is to make new connections, brainstorm ideas, develop synergies, increase opportunities for collaboration and help us build a strong, thriving, sustainable community for planetary science in Europe.
You don’t have to be a member of the Europlanet Society or the Europlanet 2024 RI project to participate in ERIM. We are looking for new people to engage with Europlanet, so everyone is welcome. However, we will be offering free accommodation and travel grants to a limited number (~150) of participants. If we are over-subscribed in requests for support, priority will be given to Europlanet Society members. (Find out about other benefits of joining the Europlanet Society).
Many different topics will be covered within the ERIM programme tracks and workshops, including:
Results of Call 3 for Transnational Access to Europlanet 2024 Research Infrastructure (RI) facilities
Europlanet 2024 RI’s Transnational Access (TA) programme offers researchers the opportunity to apply to visit planetary analogue field sites, planetary simulators and sample analysis facilities. The successful projects that will be funded through the second TA Call for applications have now been announced.
Following an anonymous peer review process, on the 108 submitted projects, 71 will be funded, of which 18 will be for visits to planetary field analogue sites and 53 to laboratory facilities. The successful projects include seven led by researchers from under represented states and eleven led by international researchers from Asia (Japan, India, South Korea) and America (Argentina, Canada, Ecuador, US).
20-EPN-61: Life in extreme environments: Distribution and importance of far-red light driven photosynthesis to primary production in Martian-like environments
Visit by Dennis Nürnberg, Freie Universität Berlin, (Germany) and Daniel Canniffe, Liverpool University (UK) to TA1.5 Makgadikgadi Salt Pans (Botswana). Dates of visit: 10-19 February 2022
The aim of this project was to confirm the richness and abundance of chlorophyll f-containing cyanobacteria, and their ability to use low-energy light to perform oxygenic photosynthesis in Martian-like environments. This study was a follow-up to a 2019 sampling trip to the sabkhas of the Western Sahara (Morocco), for which we could show that chlorophyll f-cyanobacteria are highly abundant. Here we expanded this research by collecting samples from the hypersaline environments of the Sua and Ntwetwe Pans in Makgadikgadi (Botswana). Microbial mat and rock samples containing endolithic and hypolithic phototrophs were collected. Light microscopy on site confirmed the abundance of cyanobacteria of various morphologies in most collected samples. The microbial mat samples were especially rich in cyanobacteria, forming a 1-2 mm thick layer at various depths depending on the absorption properties of the top layer.
Preliminary analyses with high-performance liquid chromatography (HPLC) in combination with hyperspectral confocal fluorescence microscopy confirmed the presence of red-shifted chlorophylls in some of these samples but to less extent as observed in the sabkhas. Genomic DNA has been extracted and will be used for sequencing and phylogenetic analyses based on 16S rRNA and specific far-red light genes. This will allow to fully evaluate the microbial diversity and their ability to perform chlorophyll f-driven oxygenic photosynthesis. In addition, the enrichment and isolation process of new chlorophyll f-containing cyanobacteria has been started by transferring the samples to growth media of various salinity and keeping them under selective far-red light illumination.
Read full report, published with kind permission by Dr Nürnberg and Dr Canniffe.
Europlanet Impact Case Study #2: Atomki – A Facility’s Story
The Institute for Nuclear Research (Atomki) is Hungary’s national centre of accelerator-based nuclear and atomic physics.
At present, Atomki employs 200 persons. It is a non-profit institution funded from national and European sources with a track record of extensive international collaboration and hosting numerous (100’s) foreign visitors. The Atomki Accelerator Centre (AAC) incorporates five ion beam facilities with various particle, charge and intensity applied to diverse issues from cultural heritage to modelling the solar system.
Atomki’s association with Europlanet originated through a personal contact between Bela Sulik, head of Atomki’s Section of Atomic and Molecular Physics, and Europlanet’s coordinator, Nigel Mason, who worked together in the early 2000s on an EU-funded research infrastructure project for small accelerators and a COST action studying radiation on living things. Bela and Nigel maintained contact over the next 15 years or so, through discussions on atomic collisions.
When Atomki installed a new Tandetron accelerator in 2018, Nigel and other members of the Europlanet team visited Hungary. This visit resulted in a plan to build an astrophysics/astrochemistry beamline that could provide irradiation measurements on analogue Solar System ices for ion energy and ion species over the range of the solar wind and low energy tail of galactic cosmic rays.
The Ice Chamber for Astrophysics/Astrochemistry (ICA) at Atomki was installed in 2019, and was ready for the first TA visits in 2020. Europlanet researchers (from senior members of staff to students) supported the Atomki team by sharing expertise and training. Due to the pandemic, several of the first visits were virtual, but physical visits have also resumed as travel restrictions have lifted. It is now the Europlanet 2024 RI’s most over-subscribed facility.
A second chamber, supplied by from Queens University Belfast, was installed through a Europlanet 2024 RI Joint Research Activity in 2021, and this is also now open for TA visits.
Europlanet Impact Case Study #1: Barbara Cavalazzi – A Researcher’s Story
Barbara Cavalazzi is a planetary geologist who studies life under extreme conditions. Her research focuses on the emergence of life on Earth, as well as astrobiology – finding out where life might evolve elsewhere in the Solar System.
Barbara first encountered Europlanet through the Transational Access (TA) programme in 2010, which supported her to visit the Hamar Laghdad carbonate mud mounds in Morocco, a Mars analogue for geological and exobiological studies.
As Europlanet looked to expand its suite of planetary analogue field sites, Barbara proposed the Dallol geothermal system in Ethiopia for characterisation as a new analogue for Mars. This characterisation was carried out as a Joint Research Activity in the Europlanet 2020 Research Infrastructure (RI) project, which was funded by the European Commission’s Horizon 2020 programme between 2015 and 2019, and the site was offered for Transnational Access from 2018 onwards. The Europlanet team, led by Barbara, published an overview in the journal Astrobiology highlighting the importance of Dallol as a field analogue for Mars and for astrobiological studies.
She is committed to creating more research collaboration opportunities in Africa and for Africa, and is coordinating the Europlanet Workshop Series, which aims to inspire and encourage planetary science and space technology development across borders in developed and developing countries and across the spectrum of academia, industry and civil society.
The programme “SPACE: Speaking Planet to Teachers Community in Ethiopia” was born in 2013 and was developed as part of the AlmaEngage project, with support from Europlanet 2020 RI. The objective has been to work with local communities, especially in rural areas, to create opportunities, for example by creating training courses for discovering the region in respect and harmony with local communities and their culture. The focus is on teacher training and the implementation of projects and courses in the school environment. Find out more:
KBSI, established in 1988, is a government-funded research institution that conducts R&D, research support and joint research related to high-tech research equipment as well as advanced analytical science technology.
The National Research Facilities & Equipment (NFEC), established by the Framework Act on Science and Technology, sits within KBSI. The role of NFEC is to provide systematic support for research infrastructure for the development of science and technology. NFEC identifies the needs and the domestic and global environmental changes required to support the advancement of research infrastructure in Korea. Its goal is to maximise R&D productivity by strategic investment in research infrastructure, promotion of co-utilisation of research infrastructure, nurturing of technical staff, and overall operational management.
The MoU and reciprocal arrangement with Europlanet 2024 RI has enabled KBSI and NFEC to provide opportunities for transnational use of facilities, widening their user communities, and to draw on Europlanet’s experience of building an international platform for knowledge exchange and collaboration. Through the pandemic, European and Korean researchers have also worked together to develop an effective programme for virtual Transnational Access visits.
By providing access to non-European facilities and analogue sites in Africa (Botswana and Ethiopia), Asia (China and South Korea) and South America (Argentina), Europlanet 2024 RI is developing collaboration with communities not necessarily used to interact with European scientists (and vice-versa). The reciprocal arrangement with Korea has demonstrated that a co-funded Transnational Access programme can operate sustainably and efficiently, strengthening the planetary science community and research institutions around the world.
Interview withDr Keewook Yi about KBSI’s participation in Europlanet’s Global Collaboration task (EPSC2022 morning briefing, Tuesday 20 September).
Europlanet Impact Case Study #4: Venus – An International Community’s Story
For around 30 years, Venus was neglected in terms of missions, with just two missions to our ‘twin’ planet compared to 22 attempted to Mars over the same time period.
In recent years, driven by the need to interpret data from exoplanet atmospheres, interest in Venus has grown. In 2021, three venusian missions were selected by international agencies (EnVision by the European Space Agency (ESA), and VERITAS and DaVinci by NASA).
A key factor for the missions has been the ability to study the surface of Venus through its opaque atmosphere.
ESA’s Venus Express, which launched in 2005, was designed as an atmospheric mission. However, a team led by DLR proposed that a small spectral window around one micrometre could be used to study the surface. This approach proved highly successful, but there was no spectral library available to interpret data.
A Europlanet 2020 Research Infrastructure (RI) Joint Research Activity, funded by the European Commission’s Horizon 2020 programme, constructed a Venus Chamber at the Planetary Spectroscopy Laboratory (PSL), which provided experimental evidence that it is indeed possible to learn about the surface of Venus from orbit. The Venus Chamber at PSL is available for Transnational Access through the Europlanet 2024 Research Infrastructure (RI) programme.
Interview with Jörn Helbert, DLR
In this interview, Jörn Helbert explains how funding from the Europlanet 2020 Research Infrastructure project supported the development of a new Venus Chamber at the Planetary Spectroscopy Laboratory (PSL) at DLR in Berlin.
3rd Call for Applications for Free Access to Laboratories and Field Sites – Reminder
The 3rd call for applications for the Europlanet 2024 Research Infrastructure (RI) Transnational Access (TA) programme is now open!
If you are interested in submitting an application, you can check the call page to find more information about the call and how to submit your application. Please note that you will need to discuss the implementation plan for with the host institute of the TA facility or field site before submitting your application. The call will close on 20 October 2022.
Please note that although the Europlanet 2024 RI TA programme is designed to primarily support planetary science and Earth science, applications from other research disciplines are also eligible and will be considered based on innovation and potential scientific and technological impact.
21-EPN-FT1-026: Biogeochemical cycling in the lake systems of the Argentinian Puna: Biogeochemical cycling in the lake systems of the Argentinian Puna: An investigation into the microbial communities of an exceptional Hesperian martian analogue
Report Summary: Fieldwork undertaken as part of the Europlanet fast track funding call took place between 16/04/22 and 26/04/22 as part of an international team of scientists from The Open University, The Università degli Studi della Tuscia, and The Universidad Nacional de Córdoba.
Fieldwork was conducted at two high-altitude Andean Lake (HAAL) sites, Laguna Negra, and Laguna de Antofagasta. The focus of the research was to collect sediment cores and water samples from Laguna de Antofagasta to assess how microbial communities change as a factor of depth within the sediment. During the trip, a total of 5 x 30 cm cores, 5 x 250 ml of lake water for culturing, and 15 x lake water samples for geochemical analysis were collected. Furthermore, environmental variables were taken with pH, temperature, conductivity, redox potential, and UV monitored. The trip was a resounding success with enough samples taken to permit the progression of my PhD. The data gained from the trip will contribute to two or three data chapters. These chapters will focus on the geochemical characterisation of the site, the microbiology of the site, and potentially simulation experiments which will focus on Noachian/Hesperian Mars relevant metabolisms. We expect to find that LDA is a suitable geochemical analogue for Gale Crater during the Noachian Hesperian transition. We also expect that the types of metabolisms found within the sediments are similar to those predicted to have been present on Noachian/Hesperian Mars.
20-EPN2-020: Towards prospecting ore deposits on Mars: remote sensing of the planetary field analogue in the Rio Tinto mining area, Spain.
Visit by Jakub Ciazela and Dariusz Marciniak, Institute of Geological Sciences, Polish Academy of Sciences (Poland) to TA1.2 Rio Tinto (Spain). Dates of visit: 17-27 March 2022
Report Summary: The Rio Tinto area hosts the largest known volcanogenic massive sulfide deposits on Earth. We have investigated 614 sites along a river bed (Fig. 1) located 3 m from each other. At each site, we investigated 5 random samples for pyrite content. The pyrite content was always estimated by 2 to 4 researchers, and the average for each site was computed. The average pyrite content in the entire investigated area is 7.0 vol.% (12.6 wt.%). We have observed two fields, 30 x 30 m, and 30 x 60 m, with average pyrite contents >50 wt.%, which should be suitable for its detection from the orbit, both with Sentinel-2 (field resolution of 10 m) and Landsat (30 m). Principle Component Analysis of the obtained spectra from Sentinel-2 (Fig. 2) gives similar results to mineralogical data we have retrieved in the field during our geological mapping.
By establishing our test field for remote sensing of sulfide deposits in a planetary field analog on Earth, we will be able to determine abundance thresholds for the detection of major sulfide phases on Mars and identify their key spectral features. Our results will help in 1) more efficient use of the current NIR Martian spectrometers to detect ore minerals and 2) designing new space instruments optimized for ore detection to include in future missions to Mars such as one developed at the Institute of Geological Sciences and the Space Research Centre of the Polish Academy of Sciences called MIRORES (Martian far-IR ORE Spectrometer).
20-EPN2-015: In-situ measurement and sampling of biosignature-hosting products in support of organics detection in the context of ExoMars/2022: In-situ measurement and sampling of biosignature-hosting products in support of organics detection in the context of ExoMars 2022
Visit by Marco Ferrari and Simone De Angelis, IAPS-INAF (Italy) to TA1.2 Rio Tinto (Spain). Dates of visit: 11-16 July 2022
Report Summary: This project aims at sampling and performing a wide set of VIS-NIR field measurements of weathering products (e.g., sulfates, clays), rocks with hydrothermal origin, and deposits showing evidence of biosignatures. To achieve this goal, during our visit we performed 195 measurement spots with the FieldSpec 4 portable spectrometer in the range of 0.35-2.5 µm and collected 47 samples in different forms. Among all the collected samples, three of them are consistent rock blocks. This is because they will be used as a test for the laboratory model of the Ma_MISS instrument that will be able to drill them and perform the spectroscopic measurements in the borehole wall.
This campaign will also allow us to confirm the capability of the Ma_MISS instrument to detect spectral signatures of organics in geological samples containing bi_osignatures. With the spectroscopic data obtained in the field and the laboratory on the collected samples, we will build a spectral database that will be useful to the scientific community.
These activities on terrestrial analogs have proven useful for understanding life in extreme conditions and how these can be preserved in the form of biological signatures and detected by the scientific instruments that will be on board future missions to Mars.
In addition, this work helps in acquiring crucial preparation for the exploitation and interpretation of the scientific data that the Ma_MISS instrument will provide during the active phase of the mission.
Oxygen isotopes are a powerful tool to determine the parent bodies of cosmic spherules, which are the entirely melted endmember of micrometeorites. After considering the fractionation processes affecting their original oxygen isotope signatures, >90% of cosmic spherules larger than 200 μm appear to be related to chondrite clans established studying chondritic meteorites.
About 10% of cosmic spherules that show clear chondritic major element compositions display unusual 16O-poor oxygen isotopic compositions that are not linked to chondritic material present in present-day meteorite collections. Simultaneously, a subset of porphyritic (Po) cosmic spherules labelled Cumulate Porphyritic Olivine (CumPo) particles exhibits textures testifying to the settling of olivine crystals during atmospheric deceleration. This unusual texture suggests these particles entered the Earth’s atmosphere at velocity of ⁓16 km s-1 , which corresponds to orbital eccentricities >0.3 and is considered higher than most asteroidal dust bands.
By establishing a potential link between the CumPo particles and a subset of the 16O-poor spherules and characterising relict mineral grains in a selection of particles from the Sør Rondane Mountains and Larkman Nunatak micrometeorite collections using the Open University NanoSIMS, a parentage with the newly defined CY carbonaceous chondrite group is proposed. This implies that about 10% of the cosmic spherules reaching the Earth’s surface have a near-Earth origin. As such connection is rare in the meteorite collection, demonstrating the importance of fully characterising the flux of micrometeorites to understand the composition of the Solar System.
Report Summary: The flux of extraterrestrial material falling to Earth is dominated by micrometeorites. They originate from asteroids and comets and their analysis provides a complementary perspective to the insights obtained from the study of larger meteorites and from space mission sample returns. Oxygen isotope compositions can be used to match micrometeorites to parent body sources based on distinctive δ17O and δ18O ratios.
We studied a population of seven giant Antarctic micrometeorites using high-precision, spatially resolved oxygen isotope analyses to measure the composition of fine-grained matrix in hydrated and dehydrated micrometeorites.
A characteristic feature of all micrometeorites was large intrasample isotopic variation (>15‰ in δ18O). In addition, most particles could be matched to known meteorite groups, including identification of CM, CV, CR and, potentially CY parentage. This is consistent with petrographic studies which conclude that the micrometeorite flux is dominated by material from hydrated carbonaceous chondrite asteroids. One particle (TAM5-30) has petrographic characteristics intermediate between the CO and CM chondrite groups. Oxygen isotope analyses of its fine-grained matrix plot either in the CO or CM chondrite fields. This particle is interpreted as a CO-like C2 ungrouped chondrite and may represent material from an otherwise unsampled parent body.
Report Summary: Evidence of a rapid increase in the radiocarbon concentration of the tree rings for the year 775 CE was initially presented by Miyake et al in 2012 (henceforth called M12). Since then, other events similar to the M12 have been confirmed for different periods. This project aims to provide new information about the increase in concentration of radiocarbon in the period of abrupt solar activity. For the study we have chosen the periods in XIth and XIIIth century CE and in VIIth century BCE, in which increase of radiocarbon concentration was noted. The samples have been collected from dendro-chronologically dated trees, and the annual rings has been extracted for measurement.
During the Europlanet TA visit in the Isotoptech Zrt. AMS laboratory, all the samples were prepared to be measured using MICADAS AMS system. Each set of measurement was accompanying with standardsamples (of known radiocarbon concentration) to control the quality of the measurement. To obtain high precision (<2 ‰) the measurement time was extended. The results show occurrence of Miyake events in analyzing periods. For the analyzing period in VIIth century we were able to determinate the occurrence during the year, by dividing the annual ring into three parts early-wood, early-late wood and late wood. During the TA visit we have possibility to learn about the procedures used in the laboratory to prepare samples (of different kinds) for radiocarbon measurement using AMS system. We had a fruitful discussion on possible future cooperation, including joint submission of a research project proposal.
Report Summary: Submarine groundwater discharge (SGD) has been shown to be an important mechanism in transporting solutes from the terrestrial to the marine environment. Despite being a well-documented process, our knowledge about the timing of offshore groundwater emplacement is extremely scarce. We aim to develop an age-dependent numerical model in our study area to investigate the relationship between SGD and the carbon cycle, whereby the obtained 14C age of the groundwater is used as a constraint. Our goal is to analyze all the carbon pools present in our cores (i.e. TIC, TOC, DIC and CH4) for 14C, so that we can correct for possible interference with the 14C-DIC signal (used for groundwater age). This is a challenge however, as the carbon content for some of these samples is extremely low.
During this two-week visit, we not only learned about the 14C preparation methods and operation of Accelerator Mass Spectrometry (AMS), but also discussed and exchanged ideas with Isotoptech AMS C-14 group scientists. Preliminary 14C results indicate that 14C depleted DIC is observed closer to the sediment-water interface for cores with anticipated SGD. This can be explained by the advective upwards transport of older groundwater. The discrepancy between the TIC and TOC 14C content at similar core depths was found to be very large, indicating that these carbon pools are affected by different processes. This mismatch might be a result of the precipitation of authigenic carbonates or microbial activity.
Report Summary: The heavy halogens are excellent tracers for volatile transport processes in the Earth’s mantle. Our understanding of their budget and distribution is, however, very limited due to their extremely low abundances in the most abundant upper mantle minerals and a lack of well-defined partition coefficients that describe their behaviour during partial melting of the Earth’s mantle.
In this project, we analysed the bromine concentration in minerals and melts of samples, which were produced during high-P-T experiments that simulated partial melting of the Earth’s mantle at Mid-Ocean-Ridge-Basalt and Ocean-Island-Basalt source regions. For this, the neutron irradiation technique was applied, which produced 80,82Kr from 79,81Br. This technique results in unmatched detection limits below the ppm-level for the determination of bromine concentrations in nominally anhydrous minerals. During the analysis, regions of interest in the respective samples were ablated with a UV-VIS-Laser at a 10s of micrometer scale. Afterwards, the noble gases were separated and analysed with the “Albatros” mass spectrometer at ETH Zürich. This allowed us to determine bromine concentrations in the melt and in individual olivine and orthopyroxene crystals.First results show that bromine indeed behaves very incompatible with first estimates of bromine partition coefficients between minerals and melt being well below 10-3. In addition, olivine seems to be the main carrier for the heavy halogens in the Earth’s upper mantle.
Report Summary: The goal of the 2022 visit was to study and measure the electron-impact induced emission from dissociation and/or ionization of CO and CO2 between 0 – 100 eV electron energy. These experiments are part of a longer-term plan to characterize the electron-impact-induced emission features of oxygen-containing molecules found in cometary environments. These data are expected to be used in future modelling and analyses of data acquired in situ during the Rosetta mission to comet 67P/Churyumov-Gerasimenko. We aim to understand the conditions in the inner coma and how electron-impact-induced emission features can probe the physical and chemical processes occurring in the near-nucleus coma environment.
During the first half of the visit, we measured electron-impact spectra of CO2 gas at multiple electron energies. Electron impact of CO2 can give rise to emission from CO, CO+, CO2+, and excited states of C and O atoms. Since the probabilities of the different reaction channels depend strongly on the collision energy, these spectral features offer a way to diagnose the conditions of plasmas containing CO2. The collected spectra and threshold measurements are in reasonable agreement with the limited data in the literature. During the second half of the visit, we measured electron-impact spectra of CO gas at numerous electron energies. Many of the spectral features for neutral CO, CO+, and atomic C and O were characterized, as a function of electron energy, for the first time. Given the time-consuming nature of the measurements, data analysis and additional measurements will continue remotely.
Full Scientific Report on the TNA visit
Dissociative electron impact excitation reactions can provide a remote diagnostic of neutral gases and the physical environment of atmospheres around planets and small bodies in our solar system. The spectral signatures of the excited collision products are unique to each species and span the UV, visible, and infrared ranges. Previous experiments on electron impact of H2O (Bodewits et al 2019) showed clear spectral differences between photo-excitation, photodissociation, and electron impact collisions with water vapour. The efficiency of the electron impact dissociative & ionizing excitation, determined by the energy-dependent cross section, provides a remote diagnostic of the emitters in astrophysical plasmas. This process and its unique spectral signatures have been used to confirm a tenuous O2 atmosphere around Callisto, in the near-nucleus coma of comet 67P/Churyumov-Gerasimenko, and the atmosphere of Ganymede (Roth et al. 2021).
In electron impact, CO2 produces strong emission from its cation, CO2+ (Ajello 1971b), and both CO and CO2 produce strong emission from the “Comet Tail Bands” of CO+ (Ajello 1971a). At lower collision energies beneath the threshold of CO+formation, the Cameron bands of CO (ultraviolet wavelengths) are excited, and electron impact collisions have been inferred from UV observations of the Cameron bands in the atmosphere of Mars (Ajello et al 2019). In most comets, CO2 and CO are second in abundance to water vapour. Both CO and CO2 have lower sublimation temperatures compared to H2O, and can sublimate from cometary nuclei at large heliocentric distances. The threshold of the strongest electron-induced emission of these species (either CO2+ from CO2, or CO+ from CO) are relatively low and can be excited in the comae of comets at large heliocentric distances. Compared to their neutral counterparts, these cations emit in wavelength ranges that are accessible from ground-based observatories. Thus, these species are of particular interest to planetary and cometary science.
During our visit to the EIF lab at Comenius University, we focused on measuring (1) the electron-impact induced emission spectra of the gases CO and CO2 and the excited collision fragments, and (2) the emission cross sections for the important spectral features. For (1), we set a fixed electron beam energy and scanned the CCD camera across the spectral range of interest. A sample of our collected spectra is shown in Figures 1 & 2, which show the electron-impact spectra of CO2 and CO at 50 eV electron energy. At 50 eV, almost every feature in the CO2 data can be identified as bands of the cation CO2+. In the CO spectrum (Fig. 2), the strongest features are from the cation CO+. We also measured the spectra at multiple electron beam energies below and above known thresholds (e.g. the threshold for CO+ formation, ~17 eV, 100 eV), and we identified emission bands of neutral CO. These bands are well-characterized in the ultraviolet beneath ~300 nm, but many of the emission cross sections for features at visible/near-IR wavelengths are not available. In many cases, cross sections are limited to a single value, typically 100 eV electron beam energy. The spectra also show emission lines of atomic O and atomic C in the near-IR.
For (2), measuring absolute cross sections, we adopted a systematic procedure. Using the overview spectra, we deduced the most probable identifications of the spectral features. With the photon detector set at a fixed wavelength, we scan the electron beam energy to measure relative cross sections, which will later be normalized and scaled to precisely known emission cross sections in literature. Interestingly, many of the molecular bands in the spectra have multiple thresholds, as shown as by the measured relative cross section of the CO2+ feature (Figure 3). In a similar measurement of a CO+ Comet Tail band (455 nm, Figure 4), our measured thresholds are consistent with data available in literature. For both sets of experiments (CO and CO2), the spectra were far richer in features than anticipated. While we are able to identify many features by comparison to theoretical models and other experiments, the cross section measurements for every feature could not be completed in a single visit. We will continue to collaborate with the EIF laboratory remotely to measure the remainder of the cross sections. It is expected that a manuscript detailing our cross section measurements on CO and CO2 will be submitted to the Astrophysical Journal Supplement Series in the coming year.
M. Ajello, 1971a, The Journal of Chemical Physics, 53, 7.
M. Ajello, 1971b, The Journal of Chemical Physics, 53, 7.
Ajello et al 2019, Journal of Geophysical Research: Space Physics, 124, 2954-2977
Figure 1: Measured electron impact-induced emission spectrum of CO2 gas at 50 eV electron energy with a 100 micron slit size. Faint atomic features are visible in the near-IR. The emission between 280 and 500 nanometers is primarily from the cation CO2+.
Figure 2: Measured electron impact-induced emission spectrum of CO gas at 50 eV electron energy with a 400 micron slit size. Faint atomic features are visible in the near-IR. The emission between 300 and 650 nanometers is primarily from the cation CO+.
Figure 3: Measured relative emission cross section of the blended CO2+ / CO+ band at 428.3 nm from electron impact of CO2 gas. Multiple thresholds are visible in the cross section as a function of collision energy, indicating that the feature is a likely blend of CO2+ and CO+ emission bands. The thresholds are consistent with theoretical values calculated from the known dissociation and excitation energies.
Figure 4: Relative emission cross section of a CO+ comet tail band (455 nm) from electron impact of CO gas. The threshold of CO+ emission (16.74 eV) is consistent with the value in the literature within the experimental uncertainties.
Figure 5: Visiting postdoc Steve Bromley and PhD student Barbora Stachova discussing the electron impact spectrum of CO gas at 100 eV electron beam energy.
Report Summary: Auroral emissions from electron impact processes provide the opportunity to remotely characterize the physical properties of plasma and neutral gases surrounding small bodies. Surprisingly, Rosetta found that outside 2 AU, atomic and molecular emission features in the inner coma were predominantly caused by dissociative electron impact excitation. These emission features provide a wealth of information on local plasma conditions and through excited fragment species, it can allow for the measurement of chemical abundances of species that may otherwise not be easily detected remotely (CO2, O2).
We conducted electron impact experiments at the electron induced fluorescence laboratory at Comenius University (Bratislava, Slovak Republic) to characterize electron-impact induced emission of fragment species in the neutral gas surrounding comets and other small bodies in our solar system. For this project, we studied collisions between electrons up to 100 eV and CO2 and CO molecules. We measured velocity-dependent emission cross sections, determine activation thresholds of relevant reactions, and construct a spectral atlas that will aid observers and astrophysical modelers.
Report Summary: Different studies reported the endurance of cyanobacteria to Mars-like conditions; however, little is known about the cellular and molecular mechanisms responsible for this resistance. The further combination of Martian UV fluxes and perchlorate ions at concentrations found on the surface of Mars increases the challenges for survival. Under this context, this study aimed to investigate the adaptability and cellular responses of metabolically active biofilms of Chroococcidiopsis CCMEE 029 to Martian surface-like conditions combined with perchlorate ions.
Biofilms obtained from cells mixed with two different Martian regolith analogs and 2.4 mM of perchlorate ions on top of an agarized regolith-based medium were exposed to unprotected Mars-like conditions for 3 days. Parameters consisted of a Mars-like atmosphere (95% CO2, 4% N2, 1% O2) constant pressure of 700 Pa, periodic photosynthetically active radiation (PAR, 400-700nm, 3W/ m²/s) and UV (4W/m²/s) irradiation for 16 h followed by 8 h of dark with diurnal cycling of relative humidity and temperature from 75% to 0% and +15ºC to -50ºC respectively. The photosynthetic yield was followed during the exposure with the Mini-PAM analyzer integrated into the Martian simulation chamber. Post-exposure analyses of cell-viability assessment, CFU capacity, and pigment autofluorescence and morphology will be performed. Proteomics analyses are ongoing in collaboration with Dr. Peter Lasch from the Robert Koch Institute, Berlin (Doellinger et al. 2020).
Overall, this study will contribute to extending our appreciation of the limits of life as we know it, from the habitability of Mars to future management of Life Support and In-Situ Resource Utilization systems.
Report Summary: Carbonaceous chondrites are likely derived from dark (C-class) asteroids. Sample return missions to dark asteroids (JAXA Hayabusa-2, OSIRIS-REx) will allow us to link specific meteorites to these possible parent bodies. The compositions of the sample return target asteroids (Ryugu and Bennu) are currently unknown, as are the compositions of other dark asteroids. Dark asteroids are important scientific targets because they may have delivered prebiotic organic molecules to the early Earth.To help address how we can determine the compositions of dark asteroids, particularly whether they are primitive, aqueously-altered, and/or heated, we conducted a series of experiments at PSL designed to address this.
Specifically, we performed heating experiments, in vacuum, on clay minerals present in carbonaceous chondrite meteorites, and measured their subsequent spectral reflectance properties, as well as on samples heated in previous experiments (clays, carbonaceous chondrites, carbonaceous chondrite analogues), focusing on the most diagnostic spectral feature relevant to dark asteroids – the 3 micron region hydroxyl/water absorption band. The results are still being analysed, but it appears that heating in vacuum and exposure to vacuum cause changes in the depth and shape of this absorption feature, as well as the albedo, spectral slope, and appearance of additional absorption features. The results of this study will provide important constraints into the composition and history of dark asteroids.
In the TA call 2 of the Europlanet 2024 framework, both hemispherical and bidirectional reflectance spectra were collected on a total of 13 meteorites. For each meteorite, spectral data were recorded between 0.2 μm and 25 μm.
The analysed meteorite samples included carbonaceous chondrites as well as non- carbonaceous chondrites that contain carbonaceous clasts and phases. The meteorites were measured as bulk, and the same 2 mm diameter for the incoming beam aperture was used. These measurements and their results will provide additional insights on the infrared spectra of meteorites and their carbon content, which will help us better understand and constrain the composition of their respective parent asteroids.