MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements
The study of the atmosphere of exoplanets orbiting white dwarfs is a largely unexplored field. With WD 0806-661 b, we present the first deep dive into the atmospheric physics and chemistry of a cold exoplanet around a white dwarf. We observed WD 0806-661 b using JWST’s Mid-InfraRed Instrument Low-Re...
Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/adbd46 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850198040423432192 |
|---|---|
| author | Maël Voyer Quentin Changeat Pierre-Olivier Lagage Pascal Tremblin Rens Waters Manuel Güdel Thomas Henning Olivier Absil David Barrado Anthony Boccaletti Jeroen Bouwman Alain Coulais Leen Decin Adrian M. Glauser John Pye Alistair Glasse René Gastaud Sarah Kendrew Polychronis Patapis Daniel Rouan Ewine F. van Dishoeck Göran Östlin Tom P. Ray Gillian Wright |
| author_facet | Maël Voyer Quentin Changeat Pierre-Olivier Lagage Pascal Tremblin Rens Waters Manuel Güdel Thomas Henning Olivier Absil David Barrado Anthony Boccaletti Jeroen Bouwman Alain Coulais Leen Decin Adrian M. Glauser John Pye Alistair Glasse René Gastaud Sarah Kendrew Polychronis Patapis Daniel Rouan Ewine F. van Dishoeck Göran Östlin Tom P. Ray Gillian Wright |
| author_sort | Maël Voyer |
| collection | DOAJ |
| description | The study of the atmosphere of exoplanets orbiting white dwarfs is a largely unexplored field. With WD 0806-661 b, we present the first deep dive into the atmospheric physics and chemistry of a cold exoplanet around a white dwarf. We observed WD 0806-661 b using JWST’s Mid-InfraRed Instrument Low-Resolution Spectrometer, covering the wavelength range from 5 to 12 μ m, and the Imager, providing us with 12.8, 15, 18, and 21 μ m photometric measurements. We carried the data reduction of those data sets, tackling second-order effects to ensure a reliable retrieval analysis. Using the T au RE x retrieval code, we inferred the pressure–temperature structure, atmospheric chemistry, mass, and radius of the planet. The spectrum of WD 0806-661 b is shaped by molecular absorption of water, ammonia, and methane, consistent with a cold Jupiter atmosphere, allowing us to retrieve their abundances. From the mixing ratio of water, ammonia, and methane we derive C/O = 0.34 ± 0.06, ${\rm{C}}/{\rm{N}}=14.{4}_{-1.8}^{+2.5}$ , and N/O = 0.023 ± 0.004 and the ratio of detected metals as a proxy for metallicity. We also derive upper limits for the abundance of CO and CO _2 (1.2 × 10 ^−6 and 1.6 × 10 ^−7 , respectively), which were not detected by our retrieval models. While our interpretation of WD 0806-661 b’s atmosphere is mostly consistent with our theoretical understanding, some results—such as the lack of evidence for water clouds, an apparent increase in the mixing ratio of ammonia at low pressure, or the retrieved mass at odds with the supposed age—remain surprising and require follow-up observational and theoretical studies to be confirmed. |
| format | Article |
| id | doaj-art-13dfb8f56c364d6886d4cff3c024e449 |
| institution | OA Journals |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-13dfb8f56c364d6886d4cff3c024e4492025-08-20T02:12:58ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019822L3810.3847/2041-8213/adbd46MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane MeasurementsMaël Voyer0https://orcid.org/0000-0002-0615-9253Quentin Changeat1https://orcid.org/0000-0001-6516-4493Pierre-Olivier Lagage2Pascal Tremblin3https://orcid.org/0000-0001-6172-3403Rens Waters4https://orcid.org/0000-0002-5462-9387Manuel Güdel5https://orcid.org/0000-0001-9818-0588Thomas Henning6https://orcid.org/0000-0002-1493-300XOlivier Absil7https://orcid.org/0000-0002-4006-6237David Barrado8https://orcid.org/0000-0002-5971-9242Anthony Boccaletti9https://orcid.org/0000-0001-9353-2724Jeroen Bouwman10https://orcid.org/0000-0003-4757-2500Alain Coulais11https://orcid.org/0000-0001-6492-7719Leen Decin12https://orcid.org/0000-0002-5342-8612Adrian M. Glauser13https://orcid.org/0000-0001-9250-1547John Pye14https://orcid.org/0000-0002-0932-4330Alistair Glasse15https://orcid.org/0000-0002-2041-2462René Gastaud16https://orcid.org/0009-0007-5200-1362Sarah Kendrew17https://orcid.org/0000-0002-7612-0469Polychronis Patapis18https://orcid.org/0000-0001-8718-3732Daniel Rouan19https://orcid.org/0000-0002-2352-1736Ewine F. van Dishoeck20https://orcid.org/0000-0001-7591-1907Göran Östlin21https://orcid.org/0000-0002-3005-1349Tom P. Ray22https://orcid.org/0000-0002-2110-1068Gillian Wright23https://orcid.org/0000-0001-7416-7936Université Paris Cité, Université Paris-Saclay , CEA, CNRS, AIM, F-91191 Gif-sur-Yvette, France ; mael.voyer@u-paris.frKapteyn Institute, University of Groningen , 9747 AD Groningen, The Netherlands; Department of Physics and Astronomy, University College London , Gower Street, WC1E 6BT, UKUniversité Paris-Saclay , Université Paris Cité, CEA, CNRS, AIM, F-91191 Gif-sur-Yvette, FranceUniversité Paris-Saclay , UVSQ, CNRS, CEA, Maison de la Simulation, 91191, Gif-sur-Yvette, FranceSRON Netherlands Institute for Space Research , Niels Bohrweg 4, 2333 CA Leiden, The Netherlands; Department of Astrophysics/IMAPP, Radboud University , PO Box 9010, 6500 GL Nijmegen, The Netherlands; HFML—FELIX. Radboud University , PO Box 9010, 6500 GL Nijmegen, The NetherlandsDepartment of Astrophysics, University of Vienna , Türkenschanzstrasse 17, 1180 Vienna, Austria; ETH Zürich, Institute for Particle Physics and Astrophysics , Wolfgang-Pauli-Strasse 27, 8093 Zürich, SwitzerlandMax-Planck-Institut für Astronomie (MPIA) , Königstuhl 17, 69117 Heidelberg, GermanySTAR Institute, Université de Liège , Allée du Six Août 19c, 4000 Liège, BelgiumCentro de Astrobiología (CAB) , CSIC-INTA, ESAC Campus, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, SpainLESIA, Observatoire de Paris, Université PSL , CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, FranceMax-Planck-Institut für Astronomie (MPIA) , Königstuhl 17, 69117 Heidelberg, GermanyUniversité Paris-Saclay , Université Paris Cité, CEA, CNRS, AIM, F-91191 Gif-sur-Yvette, France; LERMA, Observatoire de Paris, Université PSL , Sorbonne Université, CNRS, Paris, FranceInstitute of Astronomy , KU Leuven, Celestijnenlaan 200D, 3001 Leuven, BelgiumETH Zürich, Institute for Particle Physics and Astrophysics , Wolfgang-Pauli-Strasse 27, 8093 Zürich, SwitzerlandSchool of Physics & Astronomy , Space Park Leicester, University of Leicester, 92 Corporation Road, Leicester, LE4 5SP, UKUK Astronomy Technology Centre , Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UKUniversité Paris-Saclay , CEA, Département d’Electronique des Détecteurs et d’Informatique pour la Physique, 91191, Gif-sur-Yvette, FranceEuropean Space Agency , Space Telescope Science Institute, Baltimore, MD 21218, USAETH Zürich, Institute for Particle Physics and Astrophysics , Wolfgang-Pauli-Strasse 27, 8093 Zürich, SwitzerlandLESIA, Observatoire de Paris, Université PSL , CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, FranceLeiden Observatory , Leiden University, P.O. Box 9513, 2300 RA Leiden, The NetherlandsDepartment of Astronomy , Oskar Klein Centre, Stockholm University, 106 91 Stockholm, SwedenAstronomy & Astrophysics Section , School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin, D02 XF86, IrelandUK Astronomy Technology Centre , Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UKThe study of the atmosphere of exoplanets orbiting white dwarfs is a largely unexplored field. With WD 0806-661 b, we present the first deep dive into the atmospheric physics and chemistry of a cold exoplanet around a white dwarf. We observed WD 0806-661 b using JWST’s Mid-InfraRed Instrument Low-Resolution Spectrometer, covering the wavelength range from 5 to 12 μ m, and the Imager, providing us with 12.8, 15, 18, and 21 μ m photometric measurements. We carried the data reduction of those data sets, tackling second-order effects to ensure a reliable retrieval analysis. Using the T au RE x retrieval code, we inferred the pressure–temperature structure, atmospheric chemistry, mass, and radius of the planet. The spectrum of WD 0806-661 b is shaped by molecular absorption of water, ammonia, and methane, consistent with a cold Jupiter atmosphere, allowing us to retrieve their abundances. From the mixing ratio of water, ammonia, and methane we derive C/O = 0.34 ± 0.06, ${\rm{C}}/{\rm{N}}=14.{4}_{-1.8}^{+2.5}$ , and N/O = 0.023 ± 0.004 and the ratio of detected metals as a proxy for metallicity. We also derive upper limits for the abundance of CO and CO _2 (1.2 × 10 ^−6 and 1.6 × 10 ^−7 , respectively), which were not detected by our retrieval models. While our interpretation of WD 0806-661 b’s atmosphere is mostly consistent with our theoretical understanding, some results—such as the lack of evidence for water clouds, an apparent increase in the mixing ratio of ammonia at low pressure, or the retrieved mass at odds with the supposed age—remain surprising and require follow-up observational and theoretical studies to be confirmed.https://doi.org/10.3847/2041-8213/adbd46Direct imagingSpectroscopyExoplanet atmospheresJames Webb Space TelescopeBayesian statistics |
| spellingShingle | Maël Voyer Quentin Changeat Pierre-Olivier Lagage Pascal Tremblin Rens Waters Manuel Güdel Thomas Henning Olivier Absil David Barrado Anthony Boccaletti Jeroen Bouwman Alain Coulais Leen Decin Adrian M. Glauser John Pye Alistair Glasse René Gastaud Sarah Kendrew Polychronis Patapis Daniel Rouan Ewine F. van Dishoeck Göran Östlin Tom P. Ray Gillian Wright MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements The Astrophysical Journal Letters Direct imaging Spectroscopy Exoplanet atmospheres James Webb Space Telescope Bayesian statistics |
| title | MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements |
| title_full | MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements |
| title_fullStr | MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements |
| title_full_unstemmed | MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements |
| title_short | MIRI-LRS Spectrum of a Cold Exoplanet around a White Dwarf: Water, Ammonia, and Methane Measurements |
| title_sort | miri lrs spectrum of a cold exoplanet around a white dwarf water ammonia and methane measurements |
| topic | Direct imaging Spectroscopy Exoplanet atmospheres James Webb Space Telescope Bayesian statistics |
| url | https://doi.org/10.3847/2041-8213/adbd46 |
| work_keys_str_mv | AT maelvoyer mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT quentinchangeat mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT pierreolivierlagage mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT pascaltremblin mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT renswaters mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT manuelgudel mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT thomashenning mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT olivierabsil mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT davidbarrado mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT anthonyboccaletti mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT jeroenbouwman mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT alaincoulais mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT leendecin mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT adrianmglauser mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT johnpye mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT alistairglasse mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT renegastaud mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT sarahkendrew mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT polychronispatapis mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT danielrouan mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT ewinefvandishoeck mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT goranostlin mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT tompray mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements AT gillianwright mirilrsspectrumofacoldexoplanetaroundawhitedwarfwaterammoniaandmethanemeasurements |