Issue |
A&A
Volume 656, December 2021
|
|
---|---|---|
Article Number | A142 | |
Number of page(s) | 20 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202141191 | |
Published online | 15 December 2021 |
Probing the atmosphere of WASP-69 b with low- and high-resolution transmission spectroscopy
1
Landessternwarte, Zentrum für Astronomie der Universität Heidelberg,
Königstuhl 12,
69117
Heidelberg,
Germany
e-mail: skhalafi@lsw.uni-heidelberg.de
2
Max-Planck-Institut für Astronomie,
Königstuhl 17,
69117
Heidelberg,
Germany
3
Department of Physics, New York University Abu Dhabi,
PO Box 129188,
Abu Dhabi,
UAE
4
Center for Astro, Particle and Planetary Physics (CAP3), New York University Abu Dhabi,
PO Box 129188,
Abu Dhabi,
UAE
5
Leibniz-Institut für Astrophysik Potsdam,
An der Sternwarte 16,
14482
Potsdam,
Germany
6
Institut für Astrophysik, Georg-August-Universität Göttingen,
Friedrich-Hund-Platz 1,
37077
Göttingen,
Germany
7
Centro de Astrobiología (CSIC-INTA), ESAC, Camino bajo del castillo s/n,
28692
Villanueva de la Cañada,
Madrid,
Spain
8
Department of Physics, Bu-Ali Sina University,
Hamedan
65178,
Iran
9
Thüringer Landessternwarte Tautenburg,
Sternwarte 5,
07778
Tautenburg,
Germany
10
Hamburger Sternwarte, Universität Hamburg,
Gojenbergsweg 112,
21029
Hamburg,
Germany
11
Instituto de Astrofísica de Andalucía (IAA-CSIC),
Glorieta de la Astronomía s/n,
18008
Granada,
Spain
12
Centro Astronómico Hispano-Alemán, Observatorio de Calar Alto,
04550
Gérgal,
Almería,
Spain
13
Sterrewacht Leiden, Universiteit Leiden, Postbus 9513,
2300 RA,
Leiden,
The Netherlands
14
Stellar Astrophysics Centre, Aarhus Universitet, Ny Munkegade 120,
8000
Aarhus C,
Denmark
15
Astronomical Observatory, Institute of Theoretical Physics and Astronomy, Vilniaus universitetas,
Sauletekio av. 3,
10257
Vilnius,
Lithuania
16
Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften,
Schmiedlstrasse 6,
8042
Graz,
Austria
17
Institut für Astronomie, Universität Wien,
Türkenschanzstrasse 17,
1180
Wien,
Austria
18
Observatoire de Genève, Université de Genève,
Chemin des maillettes 51,
1290
Sauverny,
Switzerland
19
European Space Research and Technology Centre, European Space Agency,
Keplerlaan 1,
2201,
AZ Noordwijk,
The Netherlands
20
Facultad de Ciencias Físicas, Departamento de Física de la Tierra y Astrof ísica & IPARCOS-UCM (Instituto de Física de Partículas y del Cosmos de laUCM), Universidad Complutense de Madrid,
28040
Madrid,
Spain
21
Instituto de Astrofísica de Canarias,
c/ Vía Láctea s/n,
38205
La Laguna,
Tenerife,
Spain
22
Universidad de La Laguna, Departamento de Astrofísica,
38206
La Laguna,
Tenerife,
Spain
23
Institut de Ciéncies de l’Espai (CSIC-IEEC), Campus UAB, c/de Can Magrans s/n,
08193
Bellaterra,
Barcelona,
Spain
24
Institut d’Estudis Espacials de Catalunya (IEEC),
08034
Barcelona,
Spain
25
Centro de Astrobiología (CSIC-INTA),
Carretera de Ajalvir km 4,
Torrejón de Ardoz,
28850
Madrid,
Spain
Received:
27
April
2021
Accepted:
24
August
2021
Consideration of both low- and high-resolution transmission spectroscopy is key for obtaining a comprehensive picture of exoplanet atmospheres. In studies of transmission spectra, the continuum information is well established with low-resolution spectra, while the shapes of individual lines are best constrained with high-resolution observations. In this work, we aim to merge high- with low-resolution transmission spectroscopy to place tighter constraints on physical parameters of the atmospheres. We present the analysis of three primary transits of WASP-69 b in the visible (VIS) channel of the CARMENES instrument and perform a combined low- and high-resolution analysis using additional data from HARPS-N, OSIRIS/GTC, and WFC3/HST already available in the literature. We investigate the Na I D1 and D2 doublet, Hα, the Ca II infra-red triplet (IRT), and K I λ7699 Å lines, and we monitor the stellar photometric variability by performing long-term photometric observations with the STELLA telescope. During the first CARMENES observing night, we detected the planet Na I D2 and D1 lines at ~7 and ~3σ significance levels, respectively. We measured a D2/D1 intensity ratio of 2.5 ± 0.7, which is in agreement with previous HARPS-N observations. Our modelling of WFC3 and OSIRIS data suggests strong Rayleigh scattering, solar to super-solar water abundance, and a highly muted Na feature in the atmosphere of this planet, in agreement with previous investigations of this target. We use the continuum information retrieved from the low-resolution spectroscopy as a prior to break the degeneracy between the Na abundance, reference pressure, and thermosphere temperature for the high-resolution spectroscopic analysis. We fit the Na I D1 and D2 lines individually and find that the posterior distributions of the model parameters agree with each other within 1σ. Our results suggest that local thermodynamic equilibrium processes can explain the observed D2 /D1 ratio because the presence of haze opacity mutes the absorption features.
Key words: methods: observational / techniques: spectroscopic / planets and satellites: atmospheres / planets and satellites: composition / planets and satellites: individual: WASP-69 b / stars: activity
© ESO 2021
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