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Rimmer PB, Shorttle O. A Surface Hydrothermal Source of Nitriles and Isonitriles. Life (Basel) 2024; 14:498. [PMID: 38672768 PMCID: PMC11051382 DOI: 10.3390/life14040498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/22/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
Giant impacts can generate transient hydrogen-rich atmospheres, reducing atmospheric carbon. The reduced carbon will form hazes that rain out onto the surface and can become incorporated into the crust. Once heated, a large fraction of the carbon is converted into graphite. The result is that local regions of the Hadean crust were plausibly saturated with graphite. We explore the consequences of such a crust for a prebiotic surface hydrothermal vent scenario. We model a surface vent fed by nitrogen-rich volcanic gas from high-temperature magmas passing through graphite-saturated crust. We consider this occurring at pressures of 1-1000bar and temperatures of 1500-1700 ∘C. The equilibrium with graphite purifies the leftover gas, resulting in substantial quantities of nitriles (0.1% HCN and 1ppm HC3N) and isonitriles (0.01% HNC) relevant for prebiotic chemistry. We use these results to predict gas-phase concentrations of methyl isocyanide of ∼1 ppm. Methyl isocyanide can participate in the non-enzymatic activation and ligation of the monomeric building blocks of life, and surface or shallow hydrothermal environments provide its only known equilibrium geochemical source.
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Affiliation(s)
- Paul B. Rimmer
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, UK
| | - Oliver Shorttle
- Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, UK
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
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2
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Wilson CF, Marcq E, Gillmann C, Widemann T, Korablev O, Mueller NT, Lefèvre M, Rimmer PB, Robert S, Zolotov MY. Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus. Space Sci Rev 2024; 220:31. [PMID: 38585189 PMCID: PMC10997549 DOI: 10.1007/s11214-024-01054-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 02/01/2024] [Indexed: 04/09/2024]
Abstract
This work reviews possible signatures and potential detectability of present-day volcanically emitted material in the atmosphere of Venus. We first discuss the expected composition of volcanic gases at present time, addressing how this is related to mantle composition and atmospheric pressure. Sulfur dioxide, often used as a marker of volcanic activity in Earth's atmosphere, has been observed since late 1970s to exhibit variability at the Venus' cloud tops at time scales from hours to decades; however, this variability may be associated with solely atmospheric processes. Water vapor is identified as a particularly valuable tracer for volcanic plumes because it can be mapped from orbit at three different tropospheric altitude ranges, and because of its apparent low background variability. We note that volcanic gas plumes could be either enhanced or depleted in water vapor compared to the background atmosphere, depending on magmatic volatile composition. Non-gaseous components of volcanic plumes, such as ash grains and/or cloud aerosol particles, are another investigation target of orbital and in situ measurements. We discuss expectations of in situ and remote measurements of volcanic plumes in the atmosphere with particular focus on the upcoming DAVINCI, EnVision and VERITAS missions, as well as possible future missions.
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Affiliation(s)
- Colin F. Wilson
- European Space Agency, Keplerlaan 1, 2201, AZ Noordwijk, The Netherlands
- Physics Dept, Oxford University, Oxford, OX1 3PU UK
| | - Emmanuel Marcq
- LATMOS/IPSL, UVSQ Sorbonne Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France
| | - Cédric Gillmann
- Institut für Geophysik, Geophysical Fluid Dynamics, ETH Zurich, Sonneggstraße 5, 8092 Zürich, Switzerland
| | - Thomas Widemann
- LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
- Université Paris-Saclay, UVSQ, DYPAC, 78000 Versailles, France
| | - Oleg Korablev
- Space Research Institute (IKI), Russian Academy of Sciences, Moscow, 117997 Russia
| | - Nils T. Mueller
- Institute for Planetary Research, DLR, Rutherfordstraße 2, 12489 Berlin, Germany
- Institute of Geosciences, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany
| | - Maxence Lefèvre
- LATMOS/IPSL, UVSQ Sorbonne Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France
| | - Paul B. Rimmer
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE UK
| | - Séverine Robert
- Royal Belgian Institute for Space Aeronomy, Brussels, Belgium
| | - Mikhail Y. Zolotov
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 USA
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3
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Mráziková K, Knížek A, Saeidfirozeh H, Petera L, Civiš S, Saija F, Cassone G, Rimmer PB, Ferus M. A Novel Abiotic Pathway for Phosphine Synthesis over Acidic Dust in Venus' Atmosphere. Astrobiology 2024; 24:407-422. [PMID: 38603526 DOI: 10.1089/ast.2023.0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Recent ground-based observations of Venus have detected a single spectral feature consistent with phosphine (PH3) in the middle atmosphere, a gas which has been suggested as a biosignature on rocky planets. The presence of PH3 in the oxidized atmosphere of Venus has not yet been explained by any abiotic process. However, state-of-the-art experimental and theoretical research published in previous works demonstrated a photochemical origin of another potential biosignature-the hydride methane-from carbon dioxide over acidic mineral surfaces on Mars. The production of methane includes formation of the HC · O radical. Our density functional theory (DFT) calculations predict an energetically plausible reaction network leading to PH3, involving either HC · O or H· radicals. We suggest that, similarly to the photochemical formation of methane over acidic minerals already discussed for Mars, the origin of PH3 in Venus' atmosphere could be explained by radical chemistry starting with the reaction of ·PO with HC·O, the latter being produced by reduction of CO2 over acidic dust in upper atmospheric layers of Venus by ultraviolet radiation. HPO, H2P·O, and H3P·OH have been identified as key intermediate species in our model pathway for phosphine synthesis.
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Affiliation(s)
- Klaudia Mráziková
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia
| | - Antonín Knížek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czechia
| | - Homa Saeidfirozeh
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia
| | - Lukáš Petera
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Prague, Czechia
| | - Svatopluk Civiš
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia
| | - Franz Saija
- Institute for Physical-Chemical Processes, National Research Council of Italy (IPCF-CNR), Messina, Italy
| | - Giuseppe Cassone
- Institute for Physical-Chemical Processes, National Research Council of Italy (IPCF-CNR), Messina, Italy
| | - Paul B Rimmer
- University of Cambridge, Cavendish Astrophysics, Cambridge, United Kingdom
| | - Martin Ferus
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia
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4
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Petkowski JJ, Seager S, Grinspoon DH, Bains W, Ranjan S, Rimmer PB, Buchanan WP, Agrawal R, Mogul R, Carr CE. Astrobiological Potential of Venus Atmosphere Chemical Anomalies and Other Unexplained Cloud Properties. Astrobiology 2024; 24:343-370. [PMID: 38452176 DOI: 10.1089/ast.2022.0060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Long-standing unexplained Venus atmosphere observations and chemical anomalies point to unknown chemistry but also leave room for the possibility of life. The unexplained observations include several gases out of thermodynamic equilibrium (e.g., tens of ppm O2, the possible presence of PH3 and NH3, SO2 and H2O vertical abundance profiles), an unknown composition of large, lower cloud particles, and the "unknown absorber(s)." Here we first review relevant properties of the venusian atmosphere and then describe the atmospheric chemical anomalies and how they motivate future astrobiology missions to Venus.
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Affiliation(s)
- Janusz J Petkowski
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Faculty of Environmental Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
- JJ Scientific, Mazowieckie, Warsaw, Poland
| | - Sara Seager
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | | | - William Bains
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - Sukrit Ranjan
- Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, Arizona, USA
| | - Paul B Rimmer
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Weston P Buchanan
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana, USA
| | - Rachana Agrawal
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rakesh Mogul
- California Polytechnic University, Pomona, California, USA
| | - Christopher E Carr
- School of Aerospace Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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5
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Jiang CZ, Rimmer PB, Lozano GG, Tosca NJ, Kufner CL, Sasselov DD, Thompson SJ. Iron-sulfur chemistry can explain the ultraviolet absorber in the clouds of Venus. Sci Adv 2024; 10:eadg8826. [PMID: 38170780 PMCID: PMC10776003 DOI: 10.1126/sciadv.adg8826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
The clouds of Venus are believed to be composed of sulfuric acid (H2SO4) and minor constituents including iron-bearing compounds, and their respective concentrations vary with height in the thick Venusian atmosphere. This study experimentally investigates possible iron-bearing mineral phases that are stable under the unique conditions within Venusian clouds. Our results demonstrate that ferric iron can react with sulfuric acid to form two mineral phases: rhomboclase [(H5O2)Fe(SO4)2·3H2O] and acid ferric sulfate [(H3O)Fe(SO4)2]. A combination of these two mineral phases and dissolved Fe3+ in varying concentrations of sulfuric acid are shown to be good candidates for explaining the 200- to 300-nm and 300- to 500-nm features of the reported unknown UV absorber. We, therefore, hypothesize a rich and largely unexplored heterogeneous chemistry in the cloud droplets of Venus that has a large effect on the optical properties of the clouds and the behavior of trace gas species throughout Venus's atmosphere.
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Affiliation(s)
- Clancy Zhijian Jiang
- Department of Earth Sciences, University of Cambridge, Downing St., Cambridge CB2 3EQ, UK
| | - Paul B. Rimmer
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, UK
| | - Gabriella G. Lozano
- Harvard-Smithsonian Center for Astrophysics, Harvard University, 60 Garden Street, Cambridge, MA 02138, USA
| | - Nicholas J. Tosca
- Department of Earth Sciences, University of Cambridge, Downing St., Cambridge CB2 3EQ, UK
| | - Corinna L. Kufner
- Harvard-Smithsonian Center for Astrophysics, Harvard University, 60 Garden Street, Cambridge, MA 02138, USA
| | - Dimitar D. Sasselov
- Harvard-Smithsonian Center for Astrophysics, Harvard University, 60 Garden Street, Cambridge, MA 02138, USA
| | - Samantha J. Thompson
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, UK
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6
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Jordan S, Shorttle O, Rimmer PB. Proposed energy-metabolisms cannot explain the atmospheric chemistry of Venus. Nat Commun 2022; 13:3274. [PMID: 35701394 PMCID: PMC9198073 DOI: 10.1038/s41467-022-30804-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 05/18/2022] [Indexed: 11/14/2022] Open
Abstract
Life in the clouds of Venus, if present in sufficiently high abundance, must be affecting the atmospheric chemistry. It has been proposed that abundant Venusian life could obtain energy from its environment using three possible sulfur energy-metabolisms. These metabolisms raise the possibility of Venus’s enigmatic cloud-layer SO2-depletion being caused by life. We here couple each proposed energy-metabolism to a photochemical-kinetics code and self-consistently predict the composition of Venus’s atmosphere under the scenario that life produces the observed SO2-depletion. Using this photo-bio-chemical kinetics code, we show that all three metabolisms can produce SO2-depletions, but do so by violating other observational constraints on Venus’s atmospheric chemistry. We calculate the maximum possible biomass density of sulfur-metabolising life in the clouds, before violating observational constraints, to be ~10−5 − 10−3 mg m−3. The methods employed are equally applicable to aerial biospheres on Venus-like exoplanets, planets that are optimally poised for atmospheric characterisation in the near future. The metabolisms proposed for hypothetical life in the clouds of Venus cannot explain the planet’s atmospheric chemistry and thus a limit can be placed on the maximum allowed biomass.
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Affiliation(s)
- Sean Jordan
- Institute of Astronomy, University of Cambridge, Cambridge, UK.
| | - Oliver Shorttle
- Institute of Astronomy, University of Cambridge, Cambridge, UK.,Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Paul B Rimmer
- Department of Earth Sciences, University of Cambridge, Cambridge, UK.,Cavendish Laboratory, University of Cambridge, Cambridge, UK.,MRC Laboratory of Molecular Biology, Cambridge, UK
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7
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Bains W, Petkowski JJ, Seager S, Ranjan S, Sousa-Silva C, Rimmer PB, Zhan Z, Greaves JS, Richards AMS. Venusian phosphine: a ‘wow!’ signal in chemistry? PHOSPHORUS SULFUR 2022. [DOI: 10.1080/10426507.2021.1998051] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- William Bains
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - Janusz J. Petkowski
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sara Seager
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sukrit Ranjan
- Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, Evanston, USA
- Department of Astronomy and Astrophysics, Northwestern University, Evanston, USA
- Blue Marble Space Institute of Science, Seattle, USA
| | | | - Paul B. Rimmer
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Zhuchang Zhan
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jane S. Greaves
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - Anita M. S. Richards
- Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester, Manchester, UK
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8
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Bains W, Petkowski JJ, Seager S, Ranjan S, Sousa-Silva C, Rimmer PB, Zhan Z, Greaves JS, Richards AMS. Phosphine on Venus Cannot Be Explained by Conventional Processes. Astrobiology 2021; 21:1277-1304. [PMID: 34283644 DOI: 10.1089/ast.2020.2352] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The recent candidate detection of ∼1 ppb of phosphine in the middle atmosphere of Venus is so unexpected that it requires an exhaustive search for explanations of its origin. Phosphorus-containing species have not been modeled for Venus' atmosphere before, and our work represents the first attempt to model phosphorus species in the venusian atmosphere. We thoroughly explore the potential pathways of formation of phosphine in a venusian environment, including in the planet's atmosphere, cloud and haze layers, surface, and subsurface. We investigate gas reactions, geochemical reactions, photochemistry, and other nonequilibrium processes. None of these potential phosphine production pathways is sufficient to explain the presence of ppb phosphine levels on Venus. If PH3's presence in Venus' atmosphere is confirmed, it therefore is highly likely to be the result of a process not previously considered plausible for venusian conditions. The process could be unknown geochemistry, photochemistry, or even aerial microbial life, given that on Earth phosphine is exclusively associated with anthropogenic and biological sources. The detection of phosphine adds to the complexity of chemical processes in the venusian environment and motivates in situ follow-up sampling missions to Venus. Our analysis provides a template for investigation of phosphine as a biosignature on other worlds.
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Affiliation(s)
- William Bains
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | - Janusz J Petkowski
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Sara Seager
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Sukrit Ranjan
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Clara Sousa-Silva
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Paul B Rimmer
- Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Zhuchang Zhan
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Jane S Greaves
- School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | - Anita M S Richards
- Department of Physics and Astronomy, Jodrell Bank Centre for Astrophysics, The University of Manchester, Manchester, United Kingdom
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Rimmer PB, Thompson SJ, Xu J, Russell DA, Green NJ, Ritson DJ, Sutherland JD, Queloz DP. Timescales for Prebiotic Photochemistry Under Realistic Surface Ultraviolet Conditions. Astrobiology 2021; 21:1099-1120. [PMID: 34152196 PMCID: PMC8570677 DOI: 10.1089/ast.2020.2335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ultraviolet (UV) light has long been invoked as a source of energy for prebiotic chemical synthesis, but experimental support does not involve sources of UV light that look like the young Sun. Here we experimentally investigate whether the UV flux available on the surface of early Earth, given a favorable atmosphere, can facilitate a variety of prebiotic chemical syntheses. We construct a solar simulator for the UV light of the faint young Sun on the surface of early Earth, called StarLab. We then attempt a series of reactions testing different aspects of a prebiotic chemical scenario involving hydrogen cyanide (HCN), sulfites, and sulfides under the UV light of StarLab, including hypophosphite oxidation by UV light and hydrogen sulfide, photoreduction of HCN with bisulfite, the photoanomerization of α-thiocytidine, the production of a chemical precursor of a potentially prebiotic activating agent (nitroprusside), the photoreduction of thioanhydrouridine and thioanhydroadenosine, and the oxidation of ethanol (EtOH) by photochemically generated hydroxyl radicals. We compare the output of StarLab to the light of the faint young Sun to constrain the timescales over which these reactions would occur on the surface of early Earth. We predict that hypophosphite oxidation, HCN reduction, and photoproduction of nitroprusside would all operate on the surface of early Earth in a matter of days to weeks. The photoanomerization of α-thiocytidine would take months to complete, and the production of oxidation products from hydroxyl radicals would take years. The photoreduction of thioanhydrouridine with hydrogen sulfide did not succeed even after a long period of irradiation, providing a lower limit on the timescale of several years. The photoreduction of thioanhydroadenosine with bisulfite produced 2'-deoxyriboadenosine (dA) on the timescale of days. This suggests the plausibility of the photoproduction of purine deoxyribonucleotides, such as the photoproduction of simple sugars, proceeds more efficiently in the presence of bisulfite.
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Affiliation(s)
- Paul B. Rimmer
- Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- Address correspondence to: Paul B. Rimmer, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | | | - Jianfeng Xu
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | | | | | | | - Didier P. Queloz
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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Helling C, Rimmer PB. Lightning and charge processes in brown dwarf and exoplanet atmospheres. Philos Trans A Math Phys Eng Sci 2019; 377:20180398. [PMID: 31378171 PMCID: PMC6710897 DOI: 10.1098/rsta.2018.0398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The study of the composition of brown dwarf atmospheres helped to understand their formation and evolution. Similarly, the study of exoplanet atmospheres is expected to constrain their formation and evolutionary states. We use results from three-dimensional simulations, kinetic cloud formation and kinetic ion-neutral chemistry to investigate ionization processes that will affect their atmosphere chemistry: the dayside of super-hot Jupiters is dominated by atomic hydrogen, and not H2O. Such planetary atmospheres exhibit a substantial degree of thermal ionization and clouds only form on the nightside where lightning leaves chemical tracers (e.g. HCN) for possibly long enough to be detectable. External radiation may cause exoplanets to be enshrouded in a shell of highly ionized, H3+-forming gas and a weather-driven aurora may emerge. Brown dwarfs enable us to study the role of electron beams for the emergence of an extrasolar, weather system-driven aurora-like chemistry, and the effect of strong magnetic fields on cold atmospheric gases. Electron beams trigger the formation of H3+ in the upper atmosphere of a brown dwarf (e.g. LSR-J1835), which may react with it to form hydronium, H3O+, as a longer lived chemical tracer. Brown dwarfs and super-hot gas giants may be excellent candidates to search for H3O+ as an H3+ product. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.
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Affiliation(s)
- Christiane Helling
- Centre for Exoplanet Science, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
- e-mail:
| | - Paul B. Rimmer
- Department of Earth Sciences, University of Cambridge, Downing St, Cambridge CB2 3EQ, UK
- Cavendish Astrophysics, JJ Thomson Ave, Cambridge CB3 0HE, UK
- MRC Laboratory of Molecular Biology, Francis Crick Ave, Cambridge CB2 0QH, UK
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Rimmer PB, Shorttle O. Origin of Life's Building Blocks in Carbon- and Nitrogen-Rich Surface Hydrothermal Vents. Life (Basel) 2019; 9:E12. [PMID: 30682803 PMCID: PMC6463091 DOI: 10.3390/life9010012] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/15/2019] [Accepted: 01/19/2019] [Indexed: 11/16/2022] Open
Abstract
There are two dominant and contrasting classes of origin of life scenarios: those predicting that life emerged in submarine hydrothermal systems, where chemical disequilibrium can provide an energy source for nascent life; and those predicting that life emerged within subaerial environments, where UV catalysis of reactions may occur to form the building blocks of life. Here, we describe a prebiotically plausible environment that draws on the strengths of both scenarios: surface hydrothermal vents. We show how key feedstock molecules for prebiotic chemistry can be produced in abundance in shallow and surficial hydrothermal systems. We calculate the chemistry of volcanic gases feeding these vents over a range of pressures and basalt C/N/O contents. If ultra-reducing carbon-rich nitrogen-rich gases interact with subsurface water at a volcanic vent they result in 10 - 3 ⁻ 1 M concentrations of diacetylene (C₄H₂), acetylene (C₂H₂), cyanoacetylene (HC₃N), hydrogen cyanide (HCN), bisulfite (likely in the form of salts containing HSO₃-), hydrogen sulfide (HS-) and soluble iron in vent water. One key feedstock molecule, cyanamide (CH₂N₂), is not formed in significant quantities within this scenario, suggesting that it may need to be delivered exogenously, or formed from hydrogen cyanide either via organometallic compounds, or by some as yet-unknown chemical synthesis. Given the likely ubiquity of surface hydrothermal vents on young, hot, terrestrial planets, these results identify a prebiotically plausible local geochemical environment, which is also amenable to future lab-based simulation.
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Affiliation(s)
- Paul B Rimmer
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.
- Cavendish Astrophysics, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, UK.
- MRC Laboratory of Molecular Biology, Francis Crick Ave, Cambridge CB2 0QH, UK.
| | - Oliver Shorttle
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.
- Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK.
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Hoeijmakers HJ, Ehrenreich D, Heng K, Kitzmann D, Grimm SL, Allart R, Deitrick R, Wyttenbach A, Oreshenko M, Pino L, Rimmer PB, Molinari E, Di Fabrizio L. Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b. Nature 2018; 560:453-455. [PMID: 30111838 DOI: 10.1038/s41586-018-0401-y] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/20/2018] [Indexed: 11/09/2022]
Abstract
To constrain the formation history of an exoplanet, we need to know its chemical composition1-3. With an equilibrium temperature of about 4,050 kelvin4, the exoplanet KELT-9b (also known as HD 195689b) is an archetype of the class of ultrahot Jupiters that straddle the transition between stars and gas-giant exoplanets and are therefore useful for studying atmospheric chemistry. At these high temperatures, iron and several other transition metals are not sequestered in molecules or cloud particles and exist solely in their atomic forms5. However, despite being the most abundant transition metal in nature, iron has not hitherto been detected directly in an exoplanet because it is highly refractory. The high temperatures of KELT-9b imply that its atmosphere is a tightly constrained chemical system that is expected to be nearly in chemical equilibrium5 and cloud-free6,7, and it has been predicted that spectral lines of iron should be detectable in the visible range of wavelengths5. Here we report observations of neutral and singly ionized atomic iron (Fe and Fe+) and singly ionized atomic titanium (Ti+) in the atmosphere of KELT-9b. We identify these species using cross-correlation analysis8 of high-resolution spectra obtained as the exoplanet passed in front of its host star. Similar detections of metals in other ultrahot Jupiters will provide constraints for planetary formation theories.
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Affiliation(s)
- H Jens Hoeijmakers
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland.,University of Bern, Center for Space and Habitability, Bern, Switzerland
| | - David Ehrenreich
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland
| | - Kevin Heng
- University of Bern, Center for Space and Habitability, Bern, Switzerland.
| | - Daniel Kitzmann
- University of Bern, Center for Space and Habitability, Bern, Switzerland
| | - Simon L Grimm
- University of Bern, Center for Space and Habitability, Bern, Switzerland
| | - Romain Allart
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland
| | - Russell Deitrick
- University of Bern, Center for Space and Habitability, Bern, Switzerland
| | | | - Maria Oreshenko
- University of Bern, Center for Space and Habitability, Bern, Switzerland
| | - Lorenzo Pino
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland
| | - Paul B Rimmer
- University of Cambridge, Cavendish Astrophysics, Cambridge, UK.,MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Emilio Molinari
- INAF FGG, Telescopio Nazionale Galileo, Breña Baja, Spain.,INAF Osservatorio Astronomici di Cagliari, Selargius, Italy
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13
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Rimmer PB, Xu J, Thompson SJ, Gillen E, Sutherland JD, Queloz D. The origin of RNA precursors on exoplanets. Sci Adv 2018; 4:eaar3302. [PMID: 30083602 PMCID: PMC6070314 DOI: 10.1126/sciadv.aar3302] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 06/19/2018] [Indexed: 05/12/2023]
Abstract
Given that the macromolecular building blocks of life were likely produced photochemically in the presence of ultraviolet (UV) light, we identify some general constraints on which stars produce sufficient UV for this photochemistry. We estimate how much light is needed for the UV photochemistry by experimentally measuring the rate constant for the UV chemistry ("light chemistry", needed for prebiotic synthesis) versus the rate constants for the bimolecular reactions that happen in the absence of the UV light ("dark chemistry"). We make these measurements for representative photochemical reactions involving SO 3 2 - and HS-. By balancing the rates for the light and dark chemistry, we delineate the "abiogenesis zones" around stars of different stellar types based on whether their UV fluxes are sufficient for building up this macromolecular prebiotic inventory. We find that the SO 3 2 - light chemistry is rapid enough to build up the prebiotic inventory for stars hotter than K5 (4400 K). We show how the abiogenesis zone overlaps with the liquid water habitable zone. Stars cooler than K5 may also drive the formation of these building blocks if they are very active. The HS- light chemistry is too slow to work even for early Earth.
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Affiliation(s)
- Paul B. Rimmer
- Cavendish Astrophysics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jianfeng Xu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Samantha J. Thompson
- Cavendish Astrophysics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - Ed Gillen
- Cavendish Astrophysics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - John D. Sutherland
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Didier Queloz
- Cavendish Astrophysics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
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Helling C, Woitke P, Rimmer PB, Kamp I, Thi WF, Meijerink R. Disk evolution, element abundances and cloud properties of young gas giant planets. Life (Basel) 2014; 4:142-73. [PMID: 25370190 PMCID: PMC4187161 DOI: 10.3390/life4020142] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 03/13/2014] [Accepted: 03/18/2014] [Indexed: 11/16/2022] Open
Abstract
We discuss the chemical pre-conditions for planet formation, in terms of gas and ice abundances in a protoplanetary disk, as function of time and position, and the resulting chemical composition and cloud properties in the atmosphere when young gas giant planets form, in particular discussing the effects of unusual, non-solar carbon and oxygen abundances. Large deviations between the abundances of the host star and its gas giants seem likely to occur if the planet formation follows the core-accretion scenario. These deviations stem from the separate evolution of gas and dust in the disk, where the dust forms the planet cores, followed by the final run-away accretion of the left-over gas. This gas will contain only traces of elements like C, N and O, because those elements have frozen out as ices. PRODIMO protoplanetary disk models are used to predict the chemical evolution of gas and ice in the midplane. We find that cosmic rays play a crucial role in slowly un-blocking the CO, where the liberated oxygen forms water, which then freezes out quickly. Therefore, the C/O ratio in the gas phase is found to gradually increase with time, in a region bracketed by the water and CO ice-lines. In this regions, C/O is found to approach unity after about 5 Myrs, scaling with the cosmic ray ionization rate assumed. We then explore how the atmospheric chemistry and cloud properties in young gas giants are affected when the non-solar C/O ratios predicted by the disk models are assumed. The DRIFT cloud formation model is applied to study the formation of atmospheric clouds under the influence of varying premordial element abundances and its feedback onto the local gas. We demonstrate that element depletion by cloud formation plays a crucial role in converting an oxygen-rich atmosphere gas into carbon-rich gas when non-solar, premordial element abundances are considered as suggested by disk models.
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Affiliation(s)
- Christiane Helling
- SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh,St Andrews KY16 9SS, UK.
| | - Peter Woitke
- SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh,St Andrews KY16 9SS, UK.
| | - Paul B Rimmer
- SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh,St Andrews KY16 9SS, UK.
| | - Inga Kamp
- Kapteyn Astronomical Institute, Postbus 800, Groningen 9747 AV, The Netherlands.
| | - Wing-Fai Thi
- Laboratoire d'Astrophisique de Grenoble, CNRS/Université Joseph Fourier (UMR5571) BP 53,Grenoble cedex 9 F-38041, France.
| | - Rowin Meijerink
- Kapteyn Astronomical Institute, Postbus 800, Groningen 9747 AV, The Netherlands.
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