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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] [Key Words] [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.
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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
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3
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Edwards B, Rice M, Zingales T, Tessenyi M, Waldmann I, Tinetti G, Pascale E, Savini G, Sarkar S. Exoplanet spectroscopy and photometry with the Twinkle space telescope. EXPERIMENTAL ASTRONOMY 2018; 47:29-63. [PMID: 32684665 PMCID: PMC7357794 DOI: 10.1007/s10686-018-9611-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 11/14/2018] [Indexed: 06/11/2023]
Abstract
The Twinkle space telescope has been designed for the characterisation of exoplanets and Solar System objects. Operating in a low Earth, Sun-synchronous orbit, Twinkle is equipped with a 45 cm telescope and visible (0.4 - 1 μm) and infrared (1.3 - 4.5 μm) spectrometers which can be operated simultaneously. Twinkle is a general observatory which will provide on-demand observations of a wide variety of targets within wavelength ranges that are currently not accessible using other space telescopes or accessible only to oversubscribed observatories in the short-term future. Here we explore the ability of Twinkle's spectrometers to characterise the currently-known exoplanets. We study the spectral resolution achievable by combining multiple observations for various planetary and stellar types. We also simulate spectral retrievals for some well-known planets (HD 209458 b, GJ 3470 b and 55 Cnc e). From the exoplanets known today, we find that with a single transit or eclipse, Twinkle could probe 89 planets at low spectral resolution (R < 20) as well as 12 planets at higher resolution (R > 20) in channel 1 (1.3 - 4.5 μm). With 10 observations, the atmospheres of 144 planets could be characterised with R <20 and 81 at higher resolutions. Upcoming surveys will reveal thousands of new exoplanets, many of which will be located within Twinkle's field of regard. TESS in particular is predicted to discover many targets around bright stars which will be suitable for follow-up observations. We include these anticipated planets and find that the number of planets Twinkle could observe in the near infrared in a single transit or eclipse increases R > 20. By stacking 10 transits, there are 1185 potential targets for study at R < 20 as well as 388 planets at higher resolutions. The majority of targets are found to be large gaseous planets although by stacking multiple observations smaller planets around bright stars (e.g. 55 Cnc e) could be observed with Twinkle. Photometry and low resolution spectroscopy with Twinkle will be useful to refine planetary, stellar and orbital parameters, monitor stellar activity through time and search for transit time and duration variations (TTVs and TDVs). Refinement of these parameters could be used to in the planning of observations with larger space-based observatories such as JWST and ARIEL. For planets orbiting very bright stars, Twinkle observations at higher spectral resolution will enable us to probe the chemical and thermal properties of an atmosphere. Simultaneous coverage across a wide wavelength range will reduce the degeneracies seen with Hubble and provide access to detections of a wide range molecules. There is the potential to revisit them many times over the mission lifetime to detect variations in cloud cover.
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Affiliation(s)
- Billy Edwards
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
| | - Malena Rice
- Department of Astronomy, Yale University, Steinbach Hall, New Haven, CT 06511 USA
| | | | - Marcell Tessenyi
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
- Blue Skies Space Ltd., 69 Wilson Street, London, EC2A 2BB UK
| | - Ingo Waldmann
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
| | - Giovanna Tinetti
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
- Blue Skies Space Ltd., 69 Wilson Street, London, EC2A 2BB UK
| | - Enzo Pascale
- Dipartimento di Fisica, La Sapienza Universita di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
- School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff, CF24 3AA UK
| | - Giorgio Savini
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
- Blue Skies Space Ltd., 69 Wilson Street, London, EC2A 2BB UK
| | - Subhajit Sarkar
- School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff, CF24 3AA UK
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4
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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: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [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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