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Ahrer EM, Stevenson KB, Mansfield M, Moran SE, Brande J, Morello G, Murray CA, Nikolov NK, Petit Dit de la Roche DJM, Schlawin E, Wheatley PJ, Zieba S, Batalha NE, Damiano M, Goyal JM, Lendl M, Lothringer JD, Mukherjee S, Ohno K, Batalha NM, Battley MP, Bean JL, Beatty TG, Benneke B, Berta-Thompson ZK, Carter AL, Cubillos PE, Daylan T, Espinoza N, Gao P, Gibson NP, Gill S, Harrington J, Hu R, Kreidberg L, Lewis NK, Line MR, López-Morales M, Parmentier V, Powell DK, Sing DK, Tsai SM, Wakeford HR, Welbanks L, Alam MK, Alderson L, Allen NH, Anderson DR, Barstow JK, Bayliss D, Bell TJ, Blecic J, Bryant EM, Burleigh MR, Carone L, Casewell SL, Changeat Q, Chubb KL, Crossfield IJM, Crouzet N, Decin L, Désert JM, Feinstein AD, Flagg L, Fortney JJ, Gizis JE, Heng K, Iro N, Kempton EMR, Kendrew S, Kirk J, Knutson HA, Komacek TD, Lagage PO, Leconte J, Lustig-Yaeger J, MacDonald RJ, Mancini L, May EM, Mayne NJ, Miguel Y, Mikal-Evans T, Molaverdikhani K, Palle E, Piaulet C, Rackham BV, Redfield S, Rogers LK, Roy PA, Rustamkulov Z, Shkolnik EL, Sotzen KS, Taylor J, Tremblin P, Tucker GS, Turner JD, de Val-Borro M, Venot O, Zhang X. Early Release Science of the exoplanet WASP-39b with JWST NIRCam. Nature 2023; 614:653-658. [PMID: 36623551 PMCID: PMC9946836 DOI: 10.1038/s41586-022-05590-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/24/2022] [Indexed: 01/11/2023]
Abstract
Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining the dominant chemical processes at work and, if in equilibrium, revealing planet formation histories. Transmission spectroscopy (for example, refs. 1,2) provides the necessary means by constraining the abundances of oxygen- and carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution and high precision, which, together, are not achievable with previous observatories. Now that JWST has commenced science operations, we are able to observe exoplanets at previously uncharted wavelengths and spectral resolutions. Here we report time-series observations of the transiting exoplanet WASP-39b using JWST's Near InfraRed Camera (NIRCam). The long-wavelength spectroscopic and short-wavelength photometric light curves span 2.0-4.0 micrometres, exhibit minimal systematics and reveal well defined molecular absorption features in the planet's spectrum. Specifically, we detect gaseous water in the atmosphere and place an upper limit on the abundance of methane. The otherwise prominent carbon dioxide feature at 2.8 micrometres is largely masked by water. The best-fit chemical equilibrium models favour an atmospheric metallicity of 1-100-times solar (that is, an enrichment of elements heavier than helium relative to the Sun) and a substellar C/O ratio. The inferred high metallicity and low C/O ratio may indicate significant accretion of solid materials during planet formation (for example, refs. 3,4,) or disequilibrium processes in the upper atmosphere (for example, refs. 5,6).
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Affiliation(s)
- Eva-Maria Ahrer
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK.
- Department of Physics, University of Warwick, Coventry, UK.
| | | | | | - Sarah E Moran
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Jonathan Brande
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - Giuseppe Morello
- Instituto de Astrofísica de Canarias (IAC), Tenerife, Spain
- Departamento de Astrofísica, Universidad de La Laguna (ULL), Tenerife, Spain
- INAF- Palermo Astronomical Observatory, Piazza del Parlamento, Palermo, Italy
| | - Catriona A Murray
- Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, USA
| | | | | | | | - Peter J Wheatley
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - Sebastian Zieba
- Max Planck Institute for Astronomy, Heidelberg, Germany
- Leiden Observatory, University of Leiden, Leiden, The Netherlands
| | | | | | - Jayesh M Goyal
- School of Earth and Planetary Sciences (SEPS), National Institute of Science Education and Research (NISER), HBNI, Jatani, India
| | - Monika Lendl
- Département d'Astronomie, Université de Genève, Sauverny, Switzerland
| | | | - 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
| | - Natalie M Batalha
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
- Astrobiology Program, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Matthew P Battley
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - Jacob L Bean
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
| | - Thomas G Beatty
- Department of Astronomy, University of Wisconsin-Madison, Madison, WI, USA
| | - Björn Benneke
- Department of Physics and Institute for Research on Exoplanets, Université de Montréal, Montreal, Quebec, Canada
| | | | - Aarynn L Carter
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Patricio E Cubillos
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
- INAF - Osservatorio Astrofisico di Torino, Pino Torinese, Italy
| | - Tansu Daylan
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - Néstor Espinoza
- Space Telescope Science Institute, Baltimore, MD, USA
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - Peter Gao
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington DC, USA
| | - Neale P Gibson
- School of Physics, Trinity College Dublin, Dublin, Ireland
| | - Samuel Gill
- Department of Physics, University of Warwick, Coventry, UK
| | - Joseph Harrington
- Planetary Sciences Group, Department of Physics and Florida Space Institute, University of Central Florida, Orlando, FL, 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
| | | | - Nikole K Lewis
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - Michael R Line
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | | | - Vivien Parmentier
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Diana K Powell
- Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA
| | - David K Sing
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Shang-Min Tsai
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
| | | | - Luis Welbanks
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 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 H Allen
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - David R Anderson
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - Joanna K Barstow
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - Daniel Bayliss
- Department of Physics, University of Warwick, Coventry, UK
| | - Taylor J Bell
- BAER Institute, NASA Ames Research Center, Moffet Field, CA, 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
| | - Edward M Bryant
- Mullard Space Science Laboratory, University College London, Dorking, UK
| | | | - Ludmila Carone
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - S L Casewell
- School of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Quentin Changeat
- Space Telescope Science Institute, Baltimore, MD, USA
- European Space Agency, Space Telescope Science Institute, Baltimore, MD, USA
- Department of Physics and Astronomy, University College London, London, UK
| | - Katy L Chubb
- Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
| | - Ian J M Crossfield
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - Nicolas Crouzet
- Leiden Observatory, Leiden University, Leiden, The Netherlands
| | - 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
| | - Laura Flagg
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - Jonathan J Fortney
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - John E Gizis
- Department of Physics and Astronomy, University of Delaware, Newark, DE, USA
| | - Kevin Heng
- Department of Physics, University of Warwick, Coventry, UK
- University Observatory Munich, Ludwig Maximilian University, Munich, Germany
- ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland
| | - Nicolas Iro
- Institute for Astrophysics, University of Vienna, Vienna, Austria
| | - Eliza M-R Kempton
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - Sarah Kendrew
- European Space Agency, Space Telescope Science Institute, Baltimore, MD, USA
| | - James Kirk
- Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA
- Department of Physics, Imperial College London, London, UK
| | - Heather A Knutson
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | | | - Pierre-Olivier Lagage
- Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, Gif-sur-Yvette, France
| | - Jérémy Leconte
- Laboratoire d'Astrophysique de Bordeaux, Université de Bordeaux, Pessac, France
| | | | - Ryan J MacDonald
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
- Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
| | - Luigi Mancini
- Max Planck Institute for Astronomy, Heidelberg, Germany
- Department of Physics, University of Rome "Tor Vergata", Rome, Italy
- INAF - Turin Astrophysical Observatory, Pino Torinese, Italy
| | - E M May
- Johns Hopkins APL, Laurel, MD, USA
| | - N J Mayne
- Department of Physics and Astronomy, University of Exeter, Exeter, UK
| | - Yamila Miguel
- Leiden Observatory, University of Leiden, Leiden, The Netherlands
- SRON Netherlands Institute for Space Research, Leiden, The Netherlands
| | | | - Karan Molaverdikhani
- Max Planck Institute for Astronomy, Heidelberg, Germany
- University Observatory Munich, Ludwig Maximilian University, Munich, Germany
- Exzellenzcluster Origins, Garching, Germany
| | - Enric Palle
- Instituto de Astrofísica de Canarias (IAC), Tenerife, Spain
| | - Caroline Piaulet
- Department of Physics and Institute for Research on Exoplanets, Université de Montréal, Montreal, Quebec, Canada
| | - 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
| | - Laura K Rogers
- Institute of Astronomy, University of Cambridge, Cambridge, UK
| | - Pierre-Alexis Roy
- Department of Physics and Institute for Research on Exoplanets, Université de Montréal, Montreal, Quebec, Canada
| | - Zafar Rustamkulov
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Evgenya L Shkolnik
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - Kristin S Sotzen
- Johns Hopkins APL, Laurel, MD, USA
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Jake Taylor
- Department of Physics and Institute for Research on Exoplanets, Université de Montréal, Montreal, Quebec, Canada
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
| | - P Tremblin
- Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Jake D Turner
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | | | - Olivia Venot
- Université de Paris Cité and Univ Paris Est Creteil, CNRS, LISA, Paris, France
| | - Xi Zhang
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
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2
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Rustamkulov Z, Sing DK, Mukherjee S, May EM, Kirk J, Schlawin E, Line MR, Piaulet C, Carter AL, Batalha NE, Goyal JM, López-Morales M, Lothringer JD, MacDonald RJ, Moran SE, Stevenson KB, Wakeford HR, Espinoza N, Bean JL, Batalha NM, Benneke B, Berta-Thompson ZK, Crossfield IJM, Gao P, Kreidberg L, Powell DK, Cubillos PE, Gibson NP, Leconte J, Molaverdikhani K, Nikolov NK, Parmentier V, Roy P, Taylor J, Turner JD, Wheatley PJ, Aggarwal K, Ahrer E, Alam MK, Alderson L, Allen NH, Banerjee A, Barat S, Barrado D, Barstow JK, Bell TJ, Blecic J, Brande J, Casewell S, Changeat Q, Chubb KL, Crouzet N, Daylan T, Decin L, Désert J, Mikal-Evans T, Feinstein AD, Flagg L, Fortney JJ, Harrington J, Heng K, Hong Y, Hu R, Iro N, Kataria T, Kempton EMR, Krick J, Lendl M, Lillo-Box J, Louca A, Lustig-Yaeger J, Mancini L, Mansfield M, Mayne NJ, Miguel Y, Morello G, Ohno K, Palle E, Petit Dit de la Roche DJM, Rackham BV, Radica M, Ramos-Rosado L, Redfield S, Rogers LK, Shkolnik EL, Southworth J, Teske J, Tremblin P, Tucker GS, Venot O, Waalkes WC, Welbanks L, Zhang X, Zieba S. Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM. Nature 2023; 614:659-663. [PMID: 36623548 PMCID: PMC9946832 DOI: 10.1038/s41586-022-05677-y] [Citation(s) in RCA: 7] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/21/2022] [Indexed: 01/11/2023]
Abstract
Transmission spectroscopy1-3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species-in particular the primary carbon-bearing molecules6,7. Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP-39b8, a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec's PRISM mode9 as part of the JWST Transiting Exoplanet Community Early Release Science Team Program10-12. We robustly detect several chemical species at high significance, including Na (19σ), H2O (33σ), CO2 (28σ) and CO (7σ). The non-detection of CH4, combined with a strong CO2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO2 (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.
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Affiliation(s)
- Z Rustamkulov
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA.
| | - D 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
| | - S Mukherjee
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - E M May
- Johns Hopkins APL, Laurel, MD, USA
| | - J Kirk
- Center for Astrophysics, Harvard and Smithsonian, Cambridge, MA, USA
- Department of Physics, Imperial College London, London, UK
| | - E Schlawin
- Steward Observatory, University of Arizona, Tucson, AZ, USA
| | - M R Line
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - C Piaulet
- Institute of Research on Exoplanets, Department of Physics, University of Montreal, Montreal, Québec, Canada
| | - A L Carter
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - N E Batalha
- NASA Ames Research Center, Moffett Field, CA, USA
| | - J M Goyal
- School of Earth and Planetary Sciences, National Institute of Science Education and Research (NISER), HBNI, Jatani, India
| | - M López-Morales
- Center for Astrophysics, Harvard and Smithsonian, Cambridge, MA, USA
| | - J D Lothringer
- Department of Physics, Utah Valley University, Orem, UT, USA
| | - R J MacDonald
- Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - S E Moran
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - H R Wakeford
- School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol, UK
| | - N Espinoza
- Space Telescope Science Institute, Baltimore, MD, USA
| | - J L Bean
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
| | - N M Batalha
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - B Benneke
- Institute of Research on Exoplanets, Department of Physics, University of Montreal, Montreal, Québec, Canada
| | - Z K Berta-Thompson
- Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, USA
| | - I J M Crossfield
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - P Gao
- Earth and Planets Laboratory, Carnegie Institution of Washington, Washington, DC, USA
| | - L Kreidberg
- Max Planck Institute for Astronomy, Heidelberg, Germany
| | - D K Powell
- Harvard and Smithsonian, Center for Astrophysics, Cambridge, MA, USA
| | - P E Cubillos
- INAF - Astrophysics Observatory at Turin, Turin, Italy
| | - N P Gibson
- School of Physics, Trinity College Dublin, Dublin, Ireland
| | - J Leconte
- Laboratoire d'Astrophysique de Bordeaux, CNRS, Université de Bordeaux, Pessac, France
| | - K Molaverdikhani
- University Observatory Munich, Ludwig Maximilian University, Munich, Germany
- Exzellenzcluster Origins, Garching, Germany
| | - N K Nikolov
- Space Telescope Science Institute, Baltimore, MD, USA
| | - V Parmentier
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK
| | - P Roy
- Institute of Research on Exoplanets, Department of Physics, University of Montreal, Montreal, Québec, Canada
| | - J Taylor
- Department of Physics, University of Oxford, Oxford, UK
| | - J D Turner
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - P J Wheatley
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - K Aggarwal
- Indian Institute of Technology, Indore, Indore, India
| | - E Ahrer
- Centre for Exoplanets and Habitability, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
| | - M K Alam
- Earth and Planets Laboratory, Carnegie Institution of Washington, Washington, DC, USA
| | - L Alderson
- School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol, UK
| | - N H Allen
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - A Banerjee
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - S Barat
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands
| | - D Barrado
- Centre for Astrobiology (CSIC-INTA), European Space Astronomy Centre Campus, University of Maria de Maeztu, Madrid, Spain
| | - J K Barstow
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - T J Bell
- BAER Institute, NASA Ames Research Center, Moffet Field, Mountain View, CA, USA
| | - J Blecic
- 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, UAE
| | - J Brande
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - S Casewell
- School of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Q Changeat
- Space Telescope Science Institute, Baltimore, MD, USA
- European Space Agency (ESA), ESA Baltimore Office, Baltimore, MD, USA
- Department of Physics and Astronomy, University College London, London, UK
| | - K L Chubb
- Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
| | - N Crouzet
- Leiden Observatory, Leiden University, Leiden, the Netherlands
| | - T Daylan
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
| | - L Decin
- Department of Physics and Astronomy, KU Leuven, Leuven, Belgium
| | - J Désert
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands
| | - T Mikal-Evans
- Max Planck Institute for Astronomy, Heidelberg, Germany
| | - A D Feinstein
- Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - L Flagg
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - J J Fortney
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - J Harrington
- Planetary Science Group, Department of Physics and Florida Space Institute, University of Central Florida, Orlando, FL, USA
| | - K Heng
- University Observatory Munich, Ludwig Maximilian University, Munich, Germany
| | - Y Hong
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, NY, USA
| | - R Hu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - N Iro
- Institute for Astrophysics, University of Vienna, Vienna, Austria
| | - T Kataria
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - E M-R Kempton
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - J Krick
- California Institute of Technology, IPAC, Pasadena, CA, USA
| | - M Lendl
- Department of Astronomy, University of Geneva, Geneva, Switzerland
| | - J Lillo-Box
- Centre for Astrobiology (CSIC-INTA), European Space Astronomy Centre Campus, University of Maria de Maeztu, Madrid, Spain
| | - A Louca
- Leiden Observatory, Leiden University, Leiden, the Netherlands
| | | | - L Mancini
- Max Planck Institute for Astronomy, Heidelberg, Germany
- INAF - Astrophysics Observatory at Turin, Turin, Italy
- Department of Physics, University of Rome 'Tor Vergata', Rome, Italy
| | - M Mansfield
- Steward Observatory, University of Arizona, Tucson, AZ, USA
| | - N J Mayne
- Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Y Miguel
- Leiden Observatory, Leiden University, Leiden, the Netherlands
- SRON Netherlands Institute for Space Research, Leiden, the Netherlands
| | - G Morello
- Institute for Astrophysics of Canarias (IAC), La Laguna, Tenerife, Spain
- Department of Astrophysics, University of La Laguna, La Laguna, Tenerife, Spain
- INAF Äì Palermo Astronomical Observatory, Palermo, Italy
| | - K Ohno
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - E Palle
- Institute for Astrophysics of Canarias (IAC), La Laguna, Tenerife, Spain
| | | | - B 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
| | - M Radica
- Institute of Research on Exoplanets, Department of Physics, University of Montreal, Montreal, Québec, Canada
| | - L Ramos-Rosado
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
| | - S Redfield
- Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT, USA
| | - L K Rogers
- Institute of Astronomy, University of Cambridge, Cambridgeshire, UK
| | - E L Shkolnik
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - J Southworth
- Astrophysics Group, Keele University, Staffordshire, UK
| | - J Teske
- Earth and Planets Laboratory, Carnegie Institution of Washington, Washington, DC, USA
| | - P Tremblin
- UVSQ, CNRS, CEA, Maison de la Simulation, Université Paris-Saclay, Gif-sur-Yvette, France
| | - G S Tucker
- Department of Physics, Brown University, Providence, RI, USA
| | - O Venot
- Université de Paris Cité and Univ Paris Est Creteil, CNRS, LISA, Paris, France
| | - W C Waalkes
- Astrophysics and Planetary Sciences, University of Colorado Boulder, Boulder, CO, USA
| | - L Welbanks
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - X Zhang
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - S Zieba
- Max Planck Institute for Astronomy, Heidelberg, Germany
- Leiden Observatory, Leiden University, Leiden, the Netherlands
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Meadows VS, Reinhard CT, Arney GN, Parenteau MN, Schwieterman EW, Domagal-Goldman SD, Lincowski AP, Stapelfeldt KR, Rauer H, DasSarma S, Hegde S, Narita N, Deitrick R, Lustig-Yaeger J, Lyons TW, Siegler N, Grenfell JL. Exoplanet Biosignatures: Understanding Oxygen as a Biosignature in the Context of Its Environment. Astrobiology 2018; 18:630-662. [PMID: 29746149 PMCID: PMC6014580 DOI: 10.1089/ast.2017.1727] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 12/15/2017] [Indexed: 05/04/2023]
Abstract
We describe how environmental context can help determine whether oxygen (O2) detected in extrasolar planetary observations is more likely to have a biological source. Here we provide an in-depth, interdisciplinary example of O2 biosignature identification and observation, which serves as the prototype for the development of a general framework for biosignature assessment. Photosynthetically generated O2 is a potentially strong biosignature, and at high abundance, it was originally thought to be an unambiguous indicator for life. However, as a biosignature, O2 faces two major challenges: (1) it was only present at high abundance for a relatively short period of Earth's history and (2) we now know of several potential planetary mechanisms that can generate abundant O2 without life being present. Consequently, our ability to interpret both the presence and absence of O2 in an exoplanetary spectrum relies on understanding the environmental context. Here we examine the coevolution of life with the early Earth's environment to identify how the interplay of sources and sinks may have suppressed O2 release into the atmosphere for several billion years, producing a false negative for biologically generated O2. These studies suggest that planetary characteristics that may enhance false negatives should be considered when selecting targets for biosignature searches. We review the most recent knowledge of false positives for O2, planetary processes that may generate abundant atmospheric O2 without a biosphere. We provide examples of how future photometric, spectroscopic, and time-dependent observations of O2 and other aspects of the planetary environment can be used to rule out false positives and thereby increase our confidence that any observed O2 is indeed a biosignature. These insights will guide and inform the development of future exoplanet characterization missions. Key Words: Biosignatures-Oxygenic photosynthesis-Exoplanets-Planetary atmospheres. Astrobiology 18, 630-662.
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Affiliation(s)
- Victoria S. Meadows
- Department of Astronomy, University of Washington, Seattle, Washington
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
| | - Christopher T. Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
| | - Giada N. Arney
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Mary N. Parenteau
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
- NASA Ames Research Center, Exobiology Branch, Mountain View, California
| | - Edward W. Schwieterman
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
- Department of Earth Sciences, University of California, Riverside, California
- NASA Postdoctoral Program, Universities Space Research Association, Columbia, Maryland
- Blue Marble Space Institute of Science, Seattle, Washington
| | - Shawn D. Domagal-Goldman
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
- Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Andrew P. Lincowski
- Department of Astronomy, University of Washington, Seattle, Washington
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
| | - Karl R. Stapelfeldt
- NASA Exoplanet Exploration Program, Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
| | - Heike Rauer
- German Aerospace Center, Institute of Planetary Research, Extrasolar Planets and Atmospheres, Berlin, Germany
| | - Shiladitya DasSarma
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland
- Institute of Marine and Environmental Technology, University System of Baltimore, Maryland
| | - Siddharth Hegde
- Carl Sagan Institute, Cornell University, Ithaca, New York
- Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, New York
| | - Norio Narita
- Department of Astronomy, The University of Tokyo, Tokyo, Japan
- Astrobiology Center, NINS, Tokyo, Japan
- National Astronomical Observatory of Japan, NINS, Tokyo, Japan
| | - Russell Deitrick
- Department of Astronomy, University of Washington, Seattle, Washington
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
| | - Jacob Lustig-Yaeger
- Department of Astronomy, University of Washington, Seattle, Washington
- NASA Astrobiology Institute, Virtual Planetary Laboratory Team, Seattle, Washington
| | - Timothy W. Lyons
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
- Department of Earth Sciences, University of California, Riverside, California
| | - Nicholas Siegler
- NASA Exoplanet Exploration Program, Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California
| | - J. Lee Grenfell
- German Aerospace Center, Institute of Planetary Research, Extrasolar Planets and Atmospheres, Berlin, Germany
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Meadows VS, Arney GN, Schwieterman EW, Lustig-Yaeger J, Lincowski AP, Robinson T, Domagal-Goldman SD, Deitrick R, Barnes RK, Fleming DP, Luger R, Driscoll PE, Quinn TR, Crisp D. The Habitability of Proxima Centauri b: Environmental States and Observational Discriminants. Astrobiology 2018; 18:133-189. [PMID: 29431479 PMCID: PMC5820795 DOI: 10.1089/ast.2016.1589] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/04/2017] [Indexed: 05/21/2023]
Abstract
Proxima Centauri b provides an unprecedented opportunity to understand the evolution and nature of terrestrial planets orbiting M dwarfs. Although Proxima Cen b orbits within its star's habitable zone, multiple plausible evolutionary paths could have generated different environments that may or may not be habitable. Here, we use 1-D coupled climate-photochemical models to generate self-consistent atmospheres for several evolutionary scenarios, including high-O2, high-CO2, and more Earth-like atmospheres, with both oxic and anoxic compositions. We show that these modeled environments can be habitable or uninhabitable at Proxima Cen b's position in the habitable zone. We use radiative transfer models to generate synthetic spectra and thermal phase curves for these simulated environments, and use instrument models to explore our ability to discriminate between possible planetary states. These results are applicable not only to Proxima Cen b but to other terrestrial planets orbiting M dwarfs. Thermal phase curves may provide the first constraint on the existence of an atmosphere. We find that James Webb Space Telescope (JWST) observations longward of 10 μm could characterize atmospheric heat transport and molecular composition. Detection of ocean glint is unlikely with JWST but may be within the reach of larger-aperture telescopes. Direct imaging spectra may detect O4 absorption, which is diagnostic of massive water loss and O2 retention, rather than a photosynthetic biosphere. Similarly, strong CO2 and CO bands at wavelengths shortward of 2.5 μm would indicate a CO2-dominated atmosphere. If the planet is habitable and volatile-rich, direct imaging will be the best means of detecting habitability. Earth-like planets with microbial biospheres may be identified by the presence of CH4-which has a longer atmospheric lifetime under Proxima Centauri's incident UV-and either photosynthetically produced O2 or a hydrocarbon haze layer. Key Words: Planetary habitability and biosignatures-Planetary atmospheres-Exoplanets-Spectroscopic biosignatures-Planetary science-Proxima Centauri b. Astrobiology 18, 133-189.
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Affiliation(s)
- Victoria S. Meadows
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Giada N. Arney
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Edward W. Schwieterman
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- NASA Postdoctoral Program, Universities Space Research Association, Columbia, Maryland
- Department of Earth Sciences, University of California at Riverside, Riverside, California
| | - Jacob Lustig-Yaeger
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Andrew P. Lincowski
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Tyler Robinson
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, California
| | - Shawn D. Domagal-Goldman
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Russell Deitrick
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Rory K. Barnes
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - David P. Fleming
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Rodrigo Luger
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Peter E. Driscoll
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC
| | - Thomas R. Quinn
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - David Crisp
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
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5
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Freedman RS, Lustig-Yaeger J, Fortney JJ, Lupu RE, Marley MS, Lodders K. GASEOUS MEAN OPACITIES FOR GIANT PLANET AND ULTRACOOL DWARF ATMOSPHERES OVER A RANGE OF METALLICITIES AND TEMPERATURES. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/0067-0049/214/2/25] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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