A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

Louis-Philippe Coulombe; Björn Benneke; Ryan Challener; Anjali A. A. Piette; Lindsey S. Wiser; Megan Mansfield; Ryan J. MacDonald; Hayley Beltz; Adina D. Feinstein; Michael Radica; Arjun B. Savel; Leonardo A. Dos Santos; Jacob L. Bean; Vivien Parmentier; Ian Wong; Emily Rauscher; Thaddeus D. Komacek; Eliza M.-R. Kempton; Xianyu Tan; Mark Hammond; Neil T. Lewis; Michael R. Line; Elspeth K. H. Lee; Hinna Shivkumar; Ian J. M. Crossfield; Matthew C. Nixon; Benjamin V. Rackham; Hannah R. Wakeford; Luis Welbanks; Xi Zhang; Natalie M. Batalha; Zachory K. Berta-Thompson; Quentin Changeat; Jean-Michel Désert; Néstor Espinoza; Jayesh M. Goyal; Joseph Harrington; Heather A. Knutson; Laura Kreidberg; Mercedes López-Morales; Avi Shporer; David K. Sing; Kevin B. Stevenson; Keshav Aggarwal; Eva-Maria Ahrer; Munazza K. Alam; Taylor J. Bell; Jasmina Blecic; Claudio Caceres; Aarynn L. Carter; Sarah L. Casewell; Nicolas Crouzet; Patricio E. Cubillos; Leen Decin; Jonathan J. Fortney; Neale P. Gibson; Kevin Heng; Thomas Henning; Nicolas Iro; Sarah Kendrew; Pierre-Olivier Lagage; Jérémy Leconte; Monika Lendl; Joshua D. Lothringer; Luigi Mancini; Thomas Mikal-Evans; Karan Molaverdikhani; Nikolay K. Nikolov; Kazumasa Ohno; Enric Palle; Caroline Piaulet; Seth Redfield; Pierre-Alexis Roy; Shang-Min Tsai; Olivia Venot; Peter J. Wheatley

doi:10.1038/s41586-023-06230-1

A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

Louis-Philippe Coulombe
, Björn Benneke
, Ryan Challener
, Anjali A. A. Piette
, Lindsey S. Wiser
, Megan Mansfield
, Ryan J. MacDonald
, Hayley Beltz
, Adina D. Feinstein
, Michael Radica
, Arjun B. Savel
, Leonardo A. Dos Santos
, Jacob L. Bean
, Vivien Parmentier
, Ian Wong
, Emily Rauscher
, Thaddeus D. Komacek
, Eliza M.-R. Kempton
, Xianyu Tan
, Mark Hammond

Neil T. Lewis, Michael R. Line, Elspeth K. H. Lee, Hinna Shivkumar, Ian J. M. Crossfield, Matthew C. Nixon, Benjamin V. Rackham, Hannah R. Wakeford, Luis Welbanks, Xi Zhang, Natalie M. Batalha, Zachory K. Berta-Thompson, Quentin Changeat, Jean-Michel Désert, Néstor Espinoza, Jayesh M. Goyal, Joseph Harrington, Heather A. Knutson, Laura Kreidberg, Mercedes López-Morales, Avi Shporer, David K. Sing, Kevin B. Stevenson, Keshav Aggarwal, Eva-Maria Ahrer, Munazza K. Alam, Taylor J. Bell, Jasmina Blecic, Claudio Caceres, Aarynn L. Carter, Sarah L. Casewell, Nicolas Crouzet, Patricio E. Cubillos, Leen Decin, Jonathan J. Fortney, Neale P. Gibson, Kevin Heng, Thomas Henning, Nicolas Iro, Sarah Kendrew, Pierre-Olivier Lagage, Jérémy Leconte, Monika Lendl, Joshua D. Lothringer, Luigi Mancini, Thomas Mikal-Evans, Karan Molaverdikhani, Nikolay K. Nikolov, Kazumasa Ohno, Enric Palle, Caroline Piaulet, Seth Redfield, Pierre-Alexis Roy, Shang-Min Tsai, Olivia Venot, Peter J. Wheatley

Physics and Astronomy

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Abstract

Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope^1,2,3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis^{3,4,5,6,7,8,9,10,11,12}. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS¹³ instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H⁻, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H = 1.03^+1.11_-0.51 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.

Original language	English
Pages (from-to)	292–298
Number of pages	7
Journal	Nature
Volume	620
Issue number	7973
Early online date	31 May 2023
DOIs	https://doi.org/10.1038/s41586-023-06230-1
Publication status	Published - 10 Aug 2023

Bibliographical note

Acknowledgments:
This work is based on observations made with the NASA/ESA/CSA JWST. The data were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. These observations are associated with program JWST-ERS-01366. Support for this program was provided by NASA through a grant from the Space Telescope Science Institute. The results reported herein benefited during the design phase from collaborations and/or information exchange within NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA’s Science Mission Directorate. L.-P.C. acknowledges funding by the Technologies for Exo-Planetary Science (TEPS) Natural Sciences and Engineering Research Council of Canada (NSERC) CREATE Trainee Program. M.M., R.J.M. and L.W. acknowledge support provided by NASA through the NASA Hubble Fellowship Program. A.D.F. acknowledges support from the National Science Foundation through the Graduate Research Fellowship Program. I.W. acknowledges support provided by NASA through the NASA Postdoctoral Program. B.V.R. acknowledges support from the 51 Pegasi b Fellowship funded by the Heising-Simons Foundation.

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Coulombe, L.-P., Benneke, B., Challener, R., Piette, A. A. A., Wiser, L. S., Mansfield, M., MacDonald, R. J., Beltz, H., Feinstein, A. D., Radica, M., Savel, A. B., Dos Santos, L. A., Bean, J. L., Parmentier, V., Wong, I., Rauscher, E., Komacek, T. D., Kempton, E. M.-R., Tan, X., ... Wheatley, P. J. (2023). A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b. Nature, 620(7973), 292–298. https://doi.org/10.1038/s41586-023-06230-1

@article{41125d83ef20428ca0ee1762f9eb4142,

title = "A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b",

abstract = "Close-in giant exoplanets with temperatures greater than 2,000 K ({\textquoteleft}ultra-hot Jupiters{\textquoteright}) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope1,2,3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis3,4,5,6,7,8,9,10,11,12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance ({\textquoteleft}metallicity{\textquoteright}, M/H = 1.03+1.11-0.51 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.",

author = "Louis-Philippe Coulombe and Bj{\"o}rn Benneke and Ryan Challener and Piette, \{Anjali A. A.\} and Wiser, \{Lindsey S.\} and Megan Mansfield and MacDonald, \{Ryan J.\} and Hayley Beltz and Feinstein, \{Adina D.\} and Michael Radica and Savel, \{Arjun B.\} and \{Dos Santos\}, \{Leonardo A.\} and Bean, \{Jacob L.\} and Vivien Parmentier and Ian Wong and Emily Rauscher and Komacek, \{Thaddeus D.\} and Kempton, \{Eliza M.-R.\} and Xianyu Tan and Mark Hammond and Lewis, \{Neil T.\} and Line, \{Michael R.\} and Lee, \{Elspeth K. H.\} and Hinna Shivkumar and Crossfield, \{Ian J. M.\} and Nixon, \{Matthew C.\} and Rackham, \{Benjamin V.\} and Wakeford, \{Hannah R.\} and Luis Welbanks and Xi Zhang and Batalha, \{Natalie M.\} and Berta-Thompson, \{Zachory K.\} and Quentin Changeat and Jean-Michel D{\'e}sert and N{\'e}stor Espinoza and Goyal, \{Jayesh M.\} and Joseph Harrington and Knutson, \{Heather A.\} and Laura Kreidberg and Mercedes L{\'o}pez-Morales and Avi Shporer and Sing, \{David K.\} and Stevenson, \{Kevin B.\} and Keshav Aggarwal and Eva-Maria Ahrer and Alam, \{Munazza K.\} and Bell, \{Taylor J.\} and Jasmina Blecic and Claudio Caceres and Carter, \{Aarynn L.\} and Casewell, \{Sarah L.\} and Nicolas Crouzet and Cubillos, \{Patricio E.\} and Leen Decin and Fortney, \{Jonathan J.\} and Gibson, \{Neale P.\} and Kevin Heng and Thomas Henning and Nicolas Iro and Sarah Kendrew and Pierre-Olivier Lagage and J{\'e}r{\'e}my Leconte and Monika Lendl and Lothringer, \{Joshua D.\} and Luigi Mancini and Thomas Mikal-Evans and Karan Molaverdikhani and Nikolov, \{Nikolay K.\} and Kazumasa Ohno and Enric Palle and Caroline Piaulet and Seth Redfield and Pierre-Alexis Roy and Shang-Min Tsai and Olivia Venot and Wheatley, \{Peter J.\}",

note = "Acknowledgments: This work is based on observations made with the NASA/ESA/CSA JWST. The data were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. These observations are associated with program JWST-ERS-01366. Support for this program was provided by NASA through a grant from the Space Telescope Science Institute. The results reported herein benefited during the design phase from collaborations and/or information exchange within NASA{\textquoteright}s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA{\textquoteright}s Science Mission Directorate. L.-P.C. acknowledges funding by the Technologies for Exo-Planetary Science (TEPS) Natural Sciences and Engineering Research Council of Canada (NSERC) CREATE Trainee Program. M.M., R.J.M. and L.W. acknowledge support provided by NASA through the NASA Hubble Fellowship Program. A.D.F. acknowledges support from the National Science Foundation through the Graduate Research Fellowship Program. I.W. acknowledges support provided by NASA through the NASA Postdoctoral Program. B.V.R. acknowledges support from the 51 Pegasi b Fellowship funded by the Heising-Simons Foundation.",

year = "2023",

month = aug,

day = "10",

doi = "10.1038/s41586-023-06230-1",

language = "English",

volume = "620",

pages = "292–298",

journal = "Nature",

issn = "0028-0836",

publisher = "Nature Publishing Group",

number = "7973",

}

Coulombe, L-P, Benneke, B, Challener, R, Piette, AAA, Wiser, LS, Mansfield, M, MacDonald, RJ, Beltz, H, Feinstein, AD, Radica, M, Savel, AB, Dos Santos, LA, Bean, JL, Parmentier, V, Wong, I, Rauscher, E, Komacek, TD, Kempton, EM-R, Tan, X, Hammond, M, Lewis, NT, Line, MR, Lee, EKH, Shivkumar, H, Crossfield, IJM, Nixon, MC, Rackham, BV, Wakeford, HR, Welbanks, L, Zhang, X, Batalha, NM, Berta-Thompson, ZK, Changeat, Q, Désert, J-M, Espinoza, N, Goyal, JM, Harrington, J, Knutson, HA, Kreidberg, L, López-Morales, M, Shporer, A, Sing, DK, Stevenson, KB, Aggarwal, K, Ahrer, E-M, Alam, MK, Bell, TJ, Blecic, J, Caceres, C, Carter, AL, Casewell, SL, Crouzet, N, Cubillos, PE, Decin, L, Fortney, JJ, Gibson, NP, Heng, K, Henning, T, Iro, N, Kendrew, S, Lagage, P-O, Leconte, J, Lendl, M, Lothringer, JD, Mancini, L, Mikal-Evans, T, Molaverdikhani, K, Nikolov, NK, Ohno, K, Palle, E, Piaulet, C, Redfield, S, Roy, P-A, Tsai, S-M, Venot, O & Wheatley, PJ 2023, 'A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b', Nature, vol. 620, no. 7973, pp. 292–298. https://doi.org/10.1038/s41586-023-06230-1

TY - JOUR

T1 - A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

AU - Coulombe, Louis-Philippe

AU - Benneke, Björn

AU - Challener, Ryan

AU - Piette, Anjali A. A.

AU - Wiser, Lindsey S.

AU - Mansfield, Megan

AU - MacDonald, Ryan J.

AU - Beltz, Hayley

AU - Feinstein, Adina D.

AU - Radica, Michael

AU - Savel, Arjun B.

AU - Dos Santos, Leonardo A.

AU - Bean, Jacob L.

AU - Parmentier, Vivien

AU - Wong, Ian

AU - Rauscher, Emily

AU - Komacek, Thaddeus D.

AU - Kempton, Eliza M.-R.

AU - Tan, Xianyu

AU - Hammond, Mark

AU - Lewis, Neil T.

AU - Line, Michael R.

AU - Lee, Elspeth K. H.

AU - Shivkumar, Hinna

AU - Crossfield, Ian J. M.

AU - Nixon, Matthew C.

AU - Rackham, Benjamin V.

AU - Wakeford, Hannah R.

AU - Welbanks, Luis

AU - Zhang, Xi

AU - Batalha, Natalie M.

AU - Berta-Thompson, Zachory K.

AU - Changeat, Quentin

AU - Désert, Jean-Michel

AU - Espinoza, Néstor

AU - Goyal, Jayesh M.

AU - Harrington, Joseph

AU - Knutson, Heather A.

AU - Kreidberg, Laura

AU - López-Morales, Mercedes

AU - Shporer, Avi

AU - Sing, David K.

AU - Stevenson, Kevin B.

AU - Aggarwal, Keshav

AU - Ahrer, Eva-Maria

AU - Alam, Munazza K.

AU - Bell, Taylor J.

AU - Blecic, Jasmina

AU - Caceres, Claudio

AU - Carter, Aarynn L.

AU - Casewell, Sarah L.

AU - Crouzet, Nicolas

AU - Cubillos, Patricio E.

AU - Decin, Leen

AU - Fortney, Jonathan J.

AU - Gibson, Neale P.

AU - Heng, Kevin

AU - Henning, Thomas

AU - Iro, Nicolas

AU - Kendrew, Sarah

AU - Lagage, Pierre-Olivier

AU - Leconte, Jérémy

AU - Lendl, Monika

AU - Lothringer, Joshua D.

AU - Mancini, Luigi

AU - Mikal-Evans, Thomas

AU - Molaverdikhani, Karan

AU - Nikolov, Nikolay K.

AU - Ohno, Kazumasa

AU - Palle, Enric

AU - Piaulet, Caroline

AU - Redfield, Seth

AU - Roy, Pierre-Alexis

AU - Tsai, Shang-Min

AU - Venot, Olivia

AU - Wheatley, Peter J.

N1 - Acknowledgments: This work is based on observations made with the NASA/ESA/CSA JWST. The data were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. These observations are associated with program JWST-ERS-01366. Support for this program was provided by NASA through a grant from the Space Telescope Science Institute. The results reported herein benefited during the design phase from collaborations and/or information exchange within NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA’s Science Mission Directorate. L.-P.C. acknowledges funding by the Technologies for Exo-Planetary Science (TEPS) Natural Sciences and Engineering Research Council of Canada (NSERC) CREATE Trainee Program. M.M., R.J.M. and L.W. acknowledge support provided by NASA through the NASA Hubble Fellowship Program. A.D.F. acknowledges support from the National Science Foundation through the Graduate Research Fellowship Program. I.W. acknowledges support provided by NASA through the NASA Postdoctoral Program. B.V.R. acknowledges support from the 51 Pegasi b Fellowship funded by the Heising-Simons Foundation.

PY - 2023/8/10

Y1 - 2023/8/10

N2 - Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope1,2,3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis3,4,5,6,7,8,9,10,11,12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H = 1.03+1.11-0.51 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.

AB - Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope1,2,3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis3,4,5,6,7,8,9,10,11,12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H = 1.03+1.11-0.51 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.

U2 - 10.1038/s41586-023-06230-1

DO - 10.1038/s41586-023-06230-1

M3 - Article

SN - 0028-0836

VL - 620

SP - 292

EP - 298

JO - Nature

JF - Nature

IS - 7973

ER -

A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

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