ESPRESSO high-resolution transmission spectroscopy of WASP-76 b
Journal
Date Issued
2021
Author(s)
Tabernero, H. M.
•
Zapatero Osorio, M. R.
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Allart, R.
•
•
Casasayas-Barris, N.
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Demangeon, O.
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Ehrenreich, D.
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Lillo-Box, J.
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Lovis, C.
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Pallé, E.
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Sousa, S. G.
•
Rebolo, R.
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Santos, N. C.
•
Pepe, F.
•
•
Adibekyan, V.
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Allende Prieto, C.
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Alibert, Y.
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Barros, S. C. C.
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Bouchy, F.
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Bourrier, V.
•
•
Dumusque, X.
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Faria, J. P.
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Figueira, P.
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Génova Santos, R.
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González Hernández, J. I.
•
Hojjatpanah, S.
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Lo Curto, G.
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Lavie, B.
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Martins, C. J. A. P.
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Martins, J. H. C.
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Mehner, A.
•
•
•
Nunes, N. J.
•
•
Seidel, J. V.
•
•
Suárez Mascareño, A.
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Udry, S.
•
•
Affolter, M.
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Alves, D.
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Amate, M.
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Avila, G.
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Bandy, T.
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Benz, W.
•
•
Broeg, C.
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Cabral, A.
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Conconi, P.
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Coelho, J.
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Cumani, C.
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Deiries, S.
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Dekker, H.
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Delabre, B.
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Fragoso, A.
•
•
Genolet, L.
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Hughes, I.
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Knudstrup, J.
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Kerber, F.
•
•
Lizon, J. L.
•
Maire, C.
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Manescau, A.
•
•
Mégevand, D.
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Monteiro, M.
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Monteiro, M.
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Moschetti, M.
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Mueller, E.
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Modigliani, A.
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Oliveira, A.
•
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Pasquini, L.
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Rasilla, J. L.
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Redaelli, E.
•
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Santana-Tschudi, S.
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Santin, P.
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Santos, P.
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Segovia, A.
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Sosnowska, D.
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Spanò, P.
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Tenegi, F.
•
Iwert, O.
•
•
Abstract
Aims: We report on ESPRESSO high-resolution transmission spectroscopic observations of two primary transits of the highly irradiated, ultra-hot Jupiter-sized planet, WASP-76b. We investigated the presence of several key atomic and molecular features of interest that may reveal the atmospheric properties of the planet.
Methods: We extracted two transmission spectra of WASP-76b with R ≈ 140 000 using a procedure that allowed us to process the full ESPRESSO wavelength range (3800-7880 Å) simultaneously. We observed that at a high signal-to-noise ratio, the continuum of ESPRESSO spectra shows `wiggles', which are likely caused by an interference pattern outside the spectrograph. To search for the planetary features, we visually analysed the extracted transmission spectra and cross-correlated the observations against theoretical spectra of different atomic and molecular species.
Results: The following atomic features are detected: Li I, Na I, Mg I, Ca II, Mn I, K I, and Fe I. All are detected with a confidence level between 9.2 σ (Na I) and 2.8 σ (Mg I). We did not detect the following species: Ti I, Cr I, Ni I, TiO, VO, and ZrO. We impose the following 1 σ upper limits on their detectability: 60, 77, 122, 6, 8, and 8 ppm, respectively.
Conclusions: We report the detection of Li I on WASP-76b for the first time. In addition, we confirm the presence of Na I and Fe I as previously reported in the literature. We show that the procedure employed in this work can detect features down to the level of ~0.1% in the transmission spectrum and ~10 ppm by means of a cross-correlation method. We discuss the presence of neutral and singly ionised features in the atmosphere of WASP-76b.
Methods: We extracted two transmission spectra of WASP-76b with R ≈ 140 000 using a procedure that allowed us to process the full ESPRESSO wavelength range (3800-7880 Å) simultaneously. We observed that at a high signal-to-noise ratio, the continuum of ESPRESSO spectra shows `wiggles', which are likely caused by an interference pattern outside the spectrograph. To search for the planetary features, we visually analysed the extracted transmission spectra and cross-correlated the observations against theoretical spectra of different atomic and molecular species.
Results: The following atomic features are detected: Li I, Na I, Mg I, Ca II, Mn I, K I, and Fe I. All are detected with a confidence level between 9.2 σ (Na I) and 2.8 σ (Mg I). We did not detect the following species: Ti I, Cr I, Ni I, TiO, VO, and ZrO. We impose the following 1 σ upper limits on their detectability: 60, 77, 122, 6, 8, and 8 ppm, respectively.
Conclusions: We report the detection of Li I on WASP-76b for the first time. In addition, we confirm the presence of Na I and Fe I as previously reported in the literature. We show that the procedure employed in this work can detect features down to the level of ~0.1% in the transmission spectrum and ~10 ppm by means of a cross-correlation method. We discuss the presence of neutral and singly ionised features in the atmosphere of WASP-76b.
Based on guaranteed time observations collected at the European Southern Observatory under ESO programme 1102.C-0744 by the ESPRESSO Consortium.
Volume
646
Start page
A158
Issn Identifier
0004-6361
Ads BibCode
2021A&A...646A.158T
Rights
open.access
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