1
|
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] [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.
Collapse
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
| |
Collapse
|
2
|
Powell D, Feinstein AD, Lee EKH, Zhang M, Tsai SM, Taylor J, Kirk J, Bell T, Barstow JK, Gao P, Bean JL, Blecic J, Chubb KL, Crossfield IJM, Jordan S, Kitzmann D, Moran SE, Morello G, Moses JI, Welbanks L, Yang J, Zhang X, Ahrer EM, Bello-Arufe A, Brande J, Casewell SL, Crouzet N, Cubillos PE, Demory BO, Dyrek A, Flagg L, Hu R, Inglis J, Jones KD, Kreidberg L, López-Morales M, Lagage PO, Meier Valdés EA, Miguel Y, Parmentier V, Piette AAA, Rackham BV, Radica M, Redfield S, Stevenson KB, Wakeford HR, Aggarwal K, Alam MK, Batalha NM, Batalha NE, Benneke B, Berta-Thompson ZK, Brady RP, Caceres C, Carter AL, Désert JM, Harrington J, Iro N, Line MR, Lothringer JD, MacDonald RJ, Mancini L, Molaverdikhani K, Mukherjee S, Nixon MC, Oza AV, Palle E, Rustamkulov Z, Sing DK, Steinrueck ME, Venot O, Wheatley PJ, Yurchenko SN. Sulfur dioxide in the mid-infrared transmission spectrum of WASP-39b. Nature 2024; 626:979-983. [PMID: 38232945 PMCID: PMC10901732 DOI: 10.1038/s41586-024-07040-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/05/2024] [Indexed: 01/19/2024]
Abstract
The recent inference of sulfur dioxide (SO2) in the atmosphere of the hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1-3 suggests that photochemistry is a key process in high-temperature exoplanet atmospheres4. This is because of the low (<1 ppb) abundance of SO2 under thermochemical equilibrium compared with that produced from the photochemistry of H2O and H2S (1-10 ppm)4-9. However, the SO2 inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.05 μm and, therefore, the detection of other SO2 absorption bands at different wavelengths is needed to better constrain the SO2 abundance. Here we report the detection of SO2 spectral features at 7.7 and 8.5 μm in the 5-12-μm transmission spectrum of WASP-39b measured by the JWST Mid-Infrared Instrument (MIRI) Low Resolution Spectrometer (LRS)10. Our observations suggest an abundance of SO2 of 0.5-25 ppm (1σ range), consistent with previous findings4. As well as SO2, we find broad water-vapour absorption features, as well as an unexplained decrease in the transit depth at wavelengths longer than 10 μm. Fitting the spectrum with a grid of atmospheric forward models, we derive an atmospheric heavy-element content (metallicity) for WASP-39b of approximately 7.1-8.0 times solar and demonstrate that photochemistry shapes the spectra of WASP-39b across a broad wavelength range.
Collapse
Affiliation(s)
- Diana Powell
- Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA.
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA.
| | - Adina D Feinstein
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
| | - Elspeth K H Lee
- Center for Space and Habitability, University of Bern, Bern, Switzerland
| | - Michael Zhang
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
| | - Shang-Min Tsai
- Department of Earth Sciences, University of California, Riverside, Riverside, CA, USA
| | - Jake Taylor
- Department of Physics, University of Oxford, Oxford, UK
- Institut Trottier de Recherche sur les Exoplanètes, Université de Montréal, Montréal, Quebec, Canada
- Département de Physique, Université de Montréal, Montréal, Quebec, Canada
| | - James Kirk
- Department of Physics, Imperial College London, London, UK
| | - Taylor Bell
- Bay Area Environmental Research Institute, NASA Ames Research Center, Moffett Field, CA, USA
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, CA, USA
| | - Joanna K Barstow
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - Peter Gao
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - Jacob L Bean
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
| | - Jasmina Blecic
- Department of Physics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Center for Astro, Particle, and Planetary Physics (CAP3), New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Katy L Chubb
- Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
| | - Ian J M Crossfield
- Department of Physics & Astronomy, University of Kansas, Lawrence, KS, USA
| | - Sean Jordan
- Institute of Astronomy, University of Cambridge, Cambridge, UK
| | - Daniel Kitzmann
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
| | - Sarah E Moran
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Giuseppe Morello
- Department of Space, Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden
- Instituto de Astrofísica de Canarias (IAC), Tenerife, Spain
- INAF - Palermo Astronomical Observatory, Palermo, Italy
| | | | - Luis Welbanks
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - Jeehyun Yang
- Planetary Sciences Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Xi Zhang
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Eva-Maria Ahrer
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - Aaron Bello-Arufe
- Astrophysics Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Jonathan Brande
- Department of Physics & Astronomy, University of Kansas, Lawrence, KS, USA
| | - S L Casewell
- School of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Nicolas Crouzet
- Leiden Observatory, University of Leiden, Leiden, The Netherlands
| | - Patricio E Cubillos
- INAF - Turin Astrophysical Observatory, Pino Torinese, Italy
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - Brice-Olivier Demory
- Center for Space and Habitability, University of Bern, Bern, Switzerland
- Space and Planetary Sciences, Institute of Physics, University of Bern, Bern, Switzerland
| | - Achrène Dyrek
- Université Paris-Saclay, CEA, CNRS, AIM, Gif-sur-Yvette, France
| | - Laura Flagg
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - Renyu Hu
- Astrophysics Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Julie Inglis
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Kathryn D Jones
- Center for Space and Habitability, University of Bern, Bern, Switzerland
| | | | | | | | | | - Yamila Miguel
- Leiden Observatory, University of Leiden, Leiden, The Netherlands
- SRON Netherlands Institute for Space Research, Leiden, The Netherlands
| | - Vivien Parmentier
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, French Riviera, France
| | - Anjali A A Piette
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - Benjamin V Rackham
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michael Radica
- Institut Trottier de Recherche sur les Exoplanètes, Université de Montréal, Montréal, Quebec, Canada
- Département de Physique, Université de Montréal, Montréal, Quebec, Canada
| | - Seth Redfield
- Astronomy Department, Wesleyan University, Middletown, CT, USA
- Van Vleck Observatory, Wesleyan University, Middletown, CT, USA
| | - Kevin B Stevenson
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | | | | | - Munazza K Alam
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - Natalie M Batalha
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | | | - Björn Benneke
- Institut Trottier de Recherche sur les Exoplanètes, Université de Montréal, Montréal, Quebec, Canada
- Département de Physique, Université de Montréal, Montréal, Quebec, Canada
| | - Zach K Berta-Thompson
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, Boulder, CO, USA
| | - Ryan P Brady
- Department of Physics and Astronomy, University College London, London, UK
| | - Claudio Caceres
- Instituto de Astrofisica, Facultad Ciencias Exactas, Universidad Andres Bello, Santiago, Chile
- Centro de Astrofisica y Tecnologias Afines (CATA), Santiago, Chile
- Núcleo Milenio de Formación Planetaria (NPF), Valparaíso, Chile
| | - Aarynn L Carter
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Jean-Michel Désert
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, The Netherlands
| | - Joseph Harrington
- Planetary Sciences Group, Department of Physics and Florida Space Institute, University of Central Florida, Orlando, FL, USA
| | - Nicolas Iro
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Michael R Line
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | | | - Ryan J MacDonald
- Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
| | - Luigi Mancini
- INAF - Turin Astrophysical Observatory, Pino Torinese, Italy
- Max Planck Institute for Astronomy, Heidelberg, Germany
- Department of Physics, University of Rome "Tor Vergata", Rome, Italy
| | - Karan Molaverdikhani
- Universitäts-Sternwarte, Ludwig-Maximilians-Universität München, München, Germany
- Exzellenzcluster Origins, Garching, Germany
| | - Sagnick Mukherjee
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Matthew C Nixon
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - Apurva V Oza
- Astrophysics Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Enric Palle
- Instituto de Astrofísica de Canarias (IAC), Tenerife, Spain
| | - Zafar Rustamkulov
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - David K Sing
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | | | - Olivia Venot
- Université de Paris Cité and Université Paris-Est Creteil, CNRS, LISA, Paris, France
| | - Peter J Wheatley
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - Sergei N Yurchenko
- Department of Physics and Astronomy, University College London, London, UK
| |
Collapse
|
3
|
Tsai SM, Lee EKH, Powell D, Gao P, Zhang X, Moses J, Hébrard E, Venot O, Parmentier V, Jordan S, Hu R, Alam MK, Alderson L, Batalha NM, Bean JL, Benneke B, Bierson CJ, Brady RP, Carone L, Carter AL, Chubb KL, Inglis J, Leconte J, Line M, López-Morales M, Miguel Y, Molaverdikhani K, Rustamkulov Z, Sing DK, Stevenson KB, Wakeford HR, Yang J, Aggarwal K, Baeyens R, Barat S, de Val-Borro M, Daylan T, Fortney JJ, France K, Goyal JM, Grant D, Kirk J, Kreidberg L, Louca A, Moran SE, Mukherjee S, Nasedkin E, Ohno K, Rackham BV, Redfield S, Taylor J, Tremblin P, Visscher C, Wallack NL, Welbanks L, Youngblood A, Ahrer EM, Batalha NE, Behr P, Berta-Thompson ZK, Blecic J, Casewell SL, Crossfield IJM, Crouzet N, Cubillos PE, Decin L, Désert JM, Feinstein AD, Gibson NP, Harrington J, Heng K, Henning T, Kempton EMR, Krick J, Lagage PO, Lendl M, Lothringer JD, Mansfield M, Mayne NJ, Mikal-Evans T, Palle E, Schlawin E, Shorttle O, Wheatley PJ, Yurchenko SN. Photochemically produced SO 2 in the atmosphere of WASP-39b. Nature 2023; 617:483-487. [PMID: 37100917 PMCID: PMC10191860 DOI: 10.1038/s41586-023-05902-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 02/28/2023] [Indexed: 04/28/2023]
Abstract
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability1. However, no unambiguous photochemical products have been detected in exoplanet atmospheres so far. Recent observations from the JWST Transiting Exoplanet Community Early Release Science Program2,3 found a spectral absorption feature at 4.05 μm arising from sulfur dioxide (SO2) in the atmosphere of WASP-39b. WASP-39b is a 1.27-Jupiter-radii, Saturn-mass (0.28 MJ) gas giant exoplanet orbiting a Sun-like star with an equilibrium temperature of around 1,100 K (ref. 4). The most plausible way of generating SO2 in such an atmosphere is through photochemical processes5,6. Here we show that the SO2 distribution computed by a suite of photochemical models robustly explains the 4.05-μm spectral feature identified by JWST transmission observations7 with NIRSpec PRISM (2.7σ)8 and G395H (4.5σ)9. SO2 is produced by successive oxidation of sulfur radicals freed when hydrogen sulfide (H2S) is destroyed. The sensitivity of the SO2 feature to the enrichment of the atmosphere by heavy elements (metallicity) suggests that it can be used as a tracer of atmospheric properties, with WASP-39b exhibiting an inferred metallicity of about 10× solar. We further point out that SO2 also shows observable features at ultraviolet and thermal infrared wavelengths not available from the existing observations.
Collapse
Affiliation(s)
- Shang-Min Tsai
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK.
- Department of Earth Sciences, University of California, Riverside, Riverside, CA, USA.
| | - Elspeth K H Lee
- Center for Space and Habitability, University of Bern, Bern, Switzerland
| | - Diana Powell
- Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA
| | - Peter Gao
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - Xi Zhang
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | | | | | - Olivia Venot
- Université de Paris Cité and Univ. Paris Est Creteil, CNRS, LISA, Paris, France
| | - Vivien Parmentier
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Sean Jordan
- Institute of Astronomy, University of Cambridge, Cambridge, UK
| | - Renyu Hu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Munazza K Alam
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - Lili Alderson
- School of Physics, University of Bristol, Bristol, UK
| | - Natalie M Batalha
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Jacob L Bean
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
| | - Björn Benneke
- Department of Physics and Institute for Research on Exoplanets, Université de Montréal, Montreal, Quebec, Canada
| | - Carver J Bierson
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - Ryan P Brady
- Department of Physics and Astronomy, University College London, London, UK
| | - Ludmila Carone
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - Aarynn L Carter
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Katy L Chubb
- Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
| | - Julie Inglis
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - Jérémy Leconte
- Laboratoire d'Astrophysique de Bordeaux, Université de Bordeaux, Pessac, France
| | - Michael Line
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | | | - Yamila Miguel
- Leiden Observatory, University of Leiden, Leiden, the Netherlands
- SRON Netherlands Institute for Space Research, Leiden, the Netherlands
| | - Karan Molaverdikhani
- Universitäts-Sternwarte München, Ludwig-Maximilians-Universität München, Munich, Germany
- Exzellenzcluster Origins, Munich, Germany
| | - Zafar Rustamkulov
- Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - David K Sing
- Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD, USA
- Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Jeehyun Yang
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Robin Baeyens
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands
| | - Saugata Barat
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands
| | | | - Tansu Daylan
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - Jonathan J Fortney
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Kevin France
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
| | - Jayesh M Goyal
- School of Earth and Planetary Sciences (SEPS), National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Odisha, India
| | - David Grant
- School of Physics, University of Bristol, Bristol, UK
| | - James Kirk
- Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA
- Department of Physics, Imperial College London, London, UK
| | | | - Amy Louca
- Leiden Observatory, University of Leiden, Leiden, the Netherlands
| | - Sarah E Moran
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Sagnick Mukherjee
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | | | - Kazumasa Ohno
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Benjamin V Rackham
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Seth Redfield
- Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT, USA
| | - Jake Taylor
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
- Department of Physics and Institute for Research on Exoplanets, Université de Montréal, Montreal, Quebec, Canada
| | - Pascal Tremblin
- Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Channon Visscher
- Space Science Institute, Boulder, CO, USA
- Chemistry and Planetary Sciences, Dordt University, Sioux Center, IA, USA
| | - Nicole L Wallack
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Luis Welbanks
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | | | - Eva-Maria Ahrer
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | | | - Patrick Behr
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
| | - Zachory K Berta-Thompson
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, Boulder, CO, USA
| | - Jasmina Blecic
- Department of Physics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Center for Astro, Particle, and Planetary Physics (CAP3), New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - S L Casewell
- School of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Ian J M Crossfield
- Department of Physics & Astronomy, University of Kansas, Lawrence, KS, USA
| | - Nicolas Crouzet
- Leiden Observatory, University of Leiden, Leiden, the Netherlands
| | - Patricio E Cubillos
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
- INAF - Turin Astrophysical Observatory, Pino Torinese, Italy
| | - Leen Decin
- Institute of Astronomy, Department of Physics and Astronomy, KU Leuven, Leuven, Belgium
| | - Jean-Michel Désert
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands
| | - Adina D Feinstein
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
| | - Neale P Gibson
- School of Physics, Trinity College Dublin, Dublin, Ireland
| | - Joseph Harrington
- Planetary Sciences Group, Department of Physics and Florida Space Institute, University of Central Florida, Orlando, FL, USA
| | - Kevin Heng
- Universitäts-Sternwarte München, Ludwig-Maximilians-Universität München, Munich, Germany
- Department of Physics, University of Warwick, Coventry, UK
| | | | - Eliza M-R Kempton
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - Jessica Krick
- Infrared Processing and Analysis Center (IPAC), California Institute of Technology, Pasadena, CA, USA
| | - Pierre-Olivier Lagage
- Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Monika Lendl
- Département d'Astronomie, Université de Genève, Sauverny, Switzerland
| | | | | | - N J Mayne
- Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | | | - Enric Palle
- Instituto de Astrofísica de Canarias (IAC), Tenerife, Spain
| | | | - Oliver Shorttle
- Institute of Astronomy, University of Cambridge, Cambridge, UK
| | - Peter J Wheatley
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - Sergei N Yurchenko
- Department of Physics and Astronomy, University College London, London, UK
| |
Collapse
|
4
|
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] [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.
Collapse
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
| |
Collapse
|
5
|
Sharma S, Arya A, Cruz R, Cleaves II HJ. Automated Exploration of Prebiotic Chemical Reaction Space: Progress and Perspectives. Life (Basel) 2021; 11:1140. [PMID: 34833016 PMCID: PMC8624352 DOI: 10.3390/life11111140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/12/2022] Open
Abstract
Prebiotic chemistry often involves the study of complex systems of chemical reactions that form large networks with a large number of diverse species. Such complex systems may have given rise to emergent phenomena that ultimately led to the origin of life on Earth. The environmental conditions and processes involved in this emergence may not be fully recapitulable, making it difficult for experimentalists to study prebiotic systems in laboratory simulations. Computational chemistry offers efficient ways to study such chemical systems and identify the ones most likely to display complex properties associated with life. Here, we review tools and techniques for modelling prebiotic chemical reaction networks and outline possible ways to identify self-replicating features that are central to many origin-of-life models.
Collapse
Affiliation(s)
- Siddhant Sharma
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Department of Biochemistry, Deshbandhu College, University of Delhi, New Delhi 110019, India
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Aayush Arya
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Department of Physics, Lovely Professional University, Jalandhar-Delhi GT Road, Phagwara 144001, India
| | - Romulo Cruz
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Big Data Laboratory, Information and Communications Technology Center (CTIC), National University of Engineering, Amaru 210, Lima 15333, Peru
| | - Henderson James Cleaves II
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| |
Collapse
|
6
|
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] [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.
Collapse
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
| |
Collapse
|
7
|
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] [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.
Collapse
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
| |
Collapse
|
8
|
Photochemistry of Anoxic Abiotic Habitable Planet Atmospheres: Impact of New H2O Cross Sections. ACTA ACUST UNITED AC 2020. [DOI: 10.3847/1538-4357/ab9363] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
9
|
O2- and CO-rich Atmospheres for Potentially Habitable Environments on TRAPPIST-1 Planets. ACTA ACUST UNITED AC 2020. [DOI: 10.3847/1538-4357/ab5f07] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
10
|
Helling C, Rimmer PB. Lightning and charge processes in brown dwarf and exoplanet atmospheres. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 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] [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'.
Collapse
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
| |
Collapse
|
11
|
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] [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.
Collapse
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.
| |
Collapse
|
12
|
|
13
|
Abiotic O2 Levels on Planets around F, G, K, and M Stars: Effects of Lightning-produced Catalysts in Eliminating Oxygen False Positives. ACTA ACUST UNITED AC 2018. [DOI: 10.3847/1538-4357/aadd9b] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
14
|
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] [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.
Collapse
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
| | | |
Collapse
|
15
|
Rimmer PB, Xu J, Thompson SJ, Gillen E, Sutherland JD, Queloz D. The origin of RNA precursors on exoplanets. SCIENCE ADVANCES 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] [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.
Collapse
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
| |
Collapse
|
16
|
Sanches-Neto FO, Coutinho ND, Carvalho-Silva VH. A novel assessment of the role of the methyl radical and water formation channel in the CH 3OH + H reaction. Phys Chem Chem Phys 2018; 19:24467-24477. [PMID: 28890979 DOI: 10.1039/c7cp03806b] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A number of experimental and theoretical papers accounted almost exclusively for two channels in the reaction of atomic hydrogen with methanol: H-abstraction from the methyl (R1) and hydroxyl (R2) functional groups. Recently, several astrochemical studies claimed the importance of another channel for this reaction, which is crucial for kinetic simulations related to the abundance of molecular constituents in planetary atmospheres: methyl radical and water formation (R3 channel). Here, motivated by the lack of and uncertainties about the experimental and theoretical kinetic rate constants for the third channel, we developed first-principles Car-Parrinello molecular dynamics thermalized at two significant temperatures - 300 and 2500 K. Furthermore, the kinetic rate constant of all three channels was calculated using a high-level deformed-transition state theory (d-TST) at a benchmark electronic structure level. d-TST is shown to be suitable for describing the overall rate constant for the CH3OH + H reaction (an archetype of the moderate tunnelling regime) with the precision required for practical applications. Considering the experimental ratios at 1000 K, kR1/kR2 ≈ 0.84 and kR1/kR3 ≈ 15-40, we provided a better estimate when compared with previous theoretical work: 7.47 and 637, respectively. The combination of these procedures explicitly demonstrates the role of the third channel in a significant range of temperatures and indicates its importance considering the thermodynamic control to estimate methyl radical and water formation. We expect that these results can help to shed new light on the fundamental kinetic rate equations for the CH3OH + H reaction.
Collapse
Affiliation(s)
- Flávio O Sanches-Neto
- Grupo de Química Teórica de Anápolis Campus de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, Caixa Postal 459, 75001-970, Anápolis, GO, Brazil.
| | | | | |
Collapse
|
17
|
Burke MP, Klippenstein SJ. Ephemeral collision complexes mediate chemically termolecular transformations that affect system chemistry. Nat Chem 2017; 9:1078-1082. [DOI: 10.1038/nchem.2842] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 07/03/2017] [Indexed: 11/09/2022]
|
18
|
VULCAN
: An Open-source, Validated Chemical Kinetics
Python
Code for Exoplanetary Atmospheres. ACTA ACUST UNITED AC 2017. [DOI: 10.3847/1538-4365/228/2/20] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
19
|
Madhusudhan N, Agúndez M, Moses JI, Hu Y. Exoplanetary Atmospheres-Chemistry, Formation Conditions, and Habitability. SPACE SCIENCE REVIEWS 2016; 205:285-348. [PMID: 28057962 PMCID: PMC5207327 DOI: 10.1007/s11214-016-0254-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Characterizing the atmospheres of extrasolar planets is the new frontier in exoplanetary science. The last two decades of exoplanet discoveries have revealed that exoplanets are very common and extremely diverse in their orbital and bulk properties. We now enter a new era as we begin to investigate the chemical diversity of exoplanets, their atmospheric and interior processes, and their formation conditions. Recent developments in the field have led to unprecedented advancements in our understanding of atmospheric chemistry of exoplanets and the implications for their formation conditions. We review these developments in the present work. We review in detail the theory of atmospheric chemistry in all classes of exoplanets discovered to date, from highly irradiated gas giants, ice giants, and super-Earths, to directly imaged giant planets at large orbital separations. We then review the observational detections of chemical species in exoplanetary atmospheres of these various types using different methods, including transit spectroscopy, Doppler spectroscopy, and direct imaging. In addition to chemical detections, we discuss the advances in determining chemical abundances in these atmospheres and how such abundances are being used to constrain exoplanetary formation conditions and migration mechanisms. Finally, we review recent theoretical work on the atmospheres of habitable exoplanets, followed by a discussion of future outlook of the field.
Collapse
Affiliation(s)
- Nikku Madhusudhan
- Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
| | - Marcelino Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain,
| | - Julianne I Moses
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA,
| | - Yongyun Hu
- Laboratory for Climate and Ocean-Atmosphere Sciences, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China,
| |
Collapse
|
20
|
Moses JI, Marley MS, Zahnle K, Line MR, Fortney JJ, Barman TS, Visscher C, Lewis NK, Wolff MJ. ON THE COMPOSITION OF YOUNG, DIRECTLY IMAGED GIANT PLANETS. THE ASTROPHYSICAL JOURNAL 2016; 829:66. [PMID: 31171882 PMCID: PMC6547835 DOI: 10.3847/0004-637x/829/2/66] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The past decade has seen significant progress on the direct detection and characterization of young, self-luminous giant planets at wide orbital separations from their host stars. Some of these planets show evidence for disequilibrium processes like transport-induced quenching in their atmospheres; photochemistry may also be important, despite the large orbital distances. These disequilibrium chemical processes can alter the expected composition, spectral behavior, thermal structure, and cooling history of the planets, and can potentially confuse determinations of bulk elemental ratios, which provide important insights into planet-formation mechanisms. Using a thermo/photochemical kinetics and transport model, we investigate the extent to which disequilibrium chemistry affects the composition and spectra of directly imaged giant exoplanets. Results for specific "young Jupiters" such as HR 8799 b and 51 Eri b are presented, as are general trends as a function of planetary effective temperature, surface gravity, incident ultraviolet flux, and strength of deep atmospheric convection. We find that quenching is very important on young Jupiters, leading to CO/CH4 and N2/NH3 ratios much greater than, and H2O mixing ratios a factor of a few less than, chemical-equilibrium predictions. Photochemistry can also be important on such planets, with CO2 and HCN being key photochemical products. Carbon dioxide becomes a major constituent when stratospheric temperatures are low and recycling of water via the H2 + OH reaction becomes kinetically stifled. Young Jupiters with effective temperatures ≲700 K are in a particularly interesting photochemical regime that differs from both transiting hot Jupiters and our own solar-system giant planets.
Collapse
Affiliation(s)
- J I Moses
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
| | - M S Marley
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - K Zahnle
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - M R Line
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
| | - J J Fortney
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
| | - T S Barman
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - C Visscher
- Dordt College, Sioux Center, IA 51250, USA and Space Science Institute, Boulder, CO 80301, USA
| | - N K Lewis
- Space Telescope Science Institute, Baltimore, MD 21218, USA
| | - M J Wolff
- Space Science Institute, Boulder, CO 80301, USA
| |
Collapse
|