The Astronomical Journal (Jan 2023)
A Spectroscopic Thermometer: Individual Vibrational Band Spectroscopy with the Example of OH in the Atmosphere of WASP-33b
- Sam O. M. Wright,
- Stevanus K. Nugroho,
- Matteo Brogi,
- Neale P. Gibson,
- Ernst J. W. de Mooij,
- Ingo Waldmann,
- Jonathan Tennyson,
- Hajime Kawahara,
- Masayuki Kuzuhara,
- Teruyuki Hirano,
- Takayuki Kotani,
- Yui Kawashima,
- Kento Masuda,
- Jayne L. Birkby,
- Chris A. Watson,
- Motohide Tamura,
- Konstanze Zwintz,
- Hiroki Harakawa,
- Tomoyuki Kudo,
- Klaus Hodapp,
- Shane Jacobson,
- Mihoko Konishi,
- Takashi Kurokawa,
- Jun Nishikawa,
- Masashi Omiya,
- Takuma Serizawa,
- Akitoshi Ueda,
- Sébastien Vievard,
- Sergei N. Yurchenko
Affiliations
- Sam O. M. Wright
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, WC1E 6BT, London, UK ; [email protected]
- Stevanus K. Nugroho
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Matteo Brogi
- ORCiD
- Dipartimento di Fisica, Università degli Studi di Torino , via Pietro Giuria 1, I-10125, Torino, Italy; Department of Physics, University of Warwick , Coventry, CV4 7AL, UK; INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
- Neale P. Gibson
- ORCiD
- School of Physics, Trinity College Dublin, The University of Dublin , Dublin 2, Ireland
- Ernst J. W. de Mooij
- ORCiD
- Astrophysics Research Centre, Queen’s University Belfast, Belfast, BT7 1NN, UK
- Ingo Waldmann
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, WC1E 6BT, London, UK ; [email protected]
- Jonathan Tennyson
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, WC1E 6BT, London, UK ; [email protected]
- Hajime Kawahara
- ORCiD
- Department of of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science , Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan
- Masayuki Kuzuhara
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Teruyuki Hirano
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, School of Science, The Graduate University for Advanced Studies (SOKENDAI) , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Takayuki Kotani
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, School of Science, The Graduate University for Advanced Studies (SOKENDAI) , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Yui Kawashima
- ORCiD
- Cluster for Pioneering Research, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Kento Masuda
- ORCiD
- Department of Earth and Space Science, Osaka University , Osaka 560-0043, Japan
- Jayne L. Birkby
- ORCiD
- Astrophysics, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK
- Chris A. Watson
- ORCiD
- School of Mathematics and Physics, Queen’s University Belfast , University Road, Belfast, BT7 1NN, UK
- Motohide Tamura
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Konstanze Zwintz
- ORCiD
- Institute for Astro- and Particle Physics, University of Innsbruck , Technikerstrasse 25/8, A-6020 Innsbruck, Austria
- Hiroki Harakawa
- ORCiD
- Subaru Telescope, 650 N. Aohoku Place, Hilo, HI 96720, USA
- Tomoyuki Kudo
- ORCiD
- Subaru Telescope, 650 N. Aohoku Place, Hilo, HI 96720, USA
- Klaus Hodapp
- ORCiD
- University of Hawaii , Institute for Astronomy, 640 N. Aohoku Place, Hilo, HI 96720, USA
- Shane Jacobson
- ORCiD
- University of Hawaii , Institute for Astronomy, 640 N. Aohoku Place, Hilo, HI 96720, USA
- Mihoko Konishi
- ORCiD
- Faculty of Science and Technology, Oita University , 700 Dannoharu, Oita 870-1192, Japan
- Takashi Kurokawa
- National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Institute of Engineering, Tokyo University of Agriculture and Technology , 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
- Jun Nishikawa
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, School of Science, The Graduate University for Advanced Studies (SOKENDAI) , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Masashi Omiya
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Takuma Serizawa
- National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Institute of Engineering, Tokyo University of Agriculture and Technology , 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
- Akitoshi Ueda
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, School of Science, The Graduate University for Advanced Studies (SOKENDAI) , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Sébastien Vievard
- ORCiD
- Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Subaru Telescope, 650 N. Aohoku Place, Hilo, HI 96720, USA
- Sergei N. Yurchenko
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, WC1E 6BT, London, UK ; [email protected]
- DOI
- https://doi.org/10.3847/1538-3881/acdb75
- Journal volume & issue
-
Vol. 166,
no. 2
p. 41
Abstract
Individual vibrational band spectroscopy presents an opportunity to examine exoplanet atmospheres in detail, by distinguishing where the vibrational state populations of molecules differ from the current assumption of a Boltzmann distribution. Here, retrieving vibrational bands of OH in exoplanet atmospheres is explored using the hot Jupiter WASP-33b as an example. We simulate low-resolution spectroscopic data for observations with the JWST's NIRSpec instrument and use high-resolution observational data obtained from the Subaru InfraRed Doppler instrument (IRD). Vibrational band–specific OH cross-section sets are constructed and used in retrievals on the (simulated) low- and (real) high-resolution data. Low-resolution observations are simulated for two WASP-33b emission scenarios: under the assumption of local thermal equilibrium (LTE) and with a toy non-LTE model for vibrational excitation of selected bands. We show that mixing ratios for individual bands can be retrieved with sufficient precision to allow the vibrational population distributions of the forward models to be reconstructed. A fit for the Boltzmann distribution in the LTE case shows that the vibrational temperature is recoverable in this manner. For high-resolution, cross-correlation applications, we apply the individual vibrational band analysis to an IRD spectrum of WASP-33b, applying an “unpeeling” technique. Individual detection significances for the two strongest bands are shown to be in line with Boltzmann-distributed vibrational state populations, consistent with the effective temperature of the WASP-33b atmosphere reported previously. We show the viability of this approach for analyzing the individual vibrational state populations behind observed and simulated spectra, including reconstructing state population distributions.
Keywords
- Astronomy data modeling
- Exoplanet atmospheres
- Exoplanet atmospheric composition
- Hot Jupiters
- High resolution spectroscopy
- Near infrared astronomy
