The GAPS programme at TNG LXXXII. The first atmospheric investigation of the gas giant WASP-13 b at high resolution with GIARPS
13 affiliations
- 1INAF – Osservatorio Astrofisico di Catania , Via S. Sofia 78, 95123 Catania ,
- 2INAF – Osservatorio Astronomico di Brera , Via E. Bianchi 46, 23807 Merate (LC) ,
- 3INAF – Osservatorio Astrofisico di Torino , Via Osservatorio 20, 10025 Pino Torinese ,
- 4INAF – Osservatorio Astronomico di Palermo , Piazza del Parlamento, 1, 90134 Palermo ,
- 5University of Turin Department of Physics, , Via Pietro Giuria 1, 10125 Torino ,
- 6Université Côte d’Azur , Observatoire de la Côte d’Azur, CNRS, Lagrange, CS 34229, Nice ,
- 7Space Research Institute, Austrian Academy of Sciences , Schmiedl- strasse 6, 8042 Graz ,
- 8University of Rome ”Tor Vergata” Department of Physics, , Via della Ricerca Scientifica 1, 00133 Roma ,
- 9Fundación Galileo Galilei - INAF , Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, TF ,
- 10INAF – Osservatorio Astronomico di Roma , Via Frascati 33, I-00078 Monte Porzio Catone ,
- 11University of Palermo , Department of Physics and Chemistry ”Emilio Segré”, Via Archirafi 36, Palermo ,
- 12Centro di Ateneo di Studi e Attivitá Spaziali “G. Colombo” Universiá degli Studi di Padova , Via Venezia 15, 35131 Padova ,
- 13INAF – Osservatorio Astronomico di Padova , vicolo dell’Osservatorio 5, I-35122 Padova ,
Abstract
Low-density transiting gas giant exoplanets are key benchmarks for atmospheric studies. Despite their large-scale heights, many of them remain poorly characterised. We present the first atmospheric investigation at high-resolution of the inflated (Rp~1.4 RJ), hot Jupiter (T~1500 K) WASP-13 b aiming at constraining its atmospheric composition and refine its orbital geometry. We analysed four transits observed with GIARPS at the TNG. Updated stellar and planetary parameters were re-derived from the most precise literature values, and a new Rossiter-McLaughlin analysis was performed to measure the projected spin-orbit angle (λ) and stellar rotational velocity (vsin i⋆). Atmospheric signals were searched using high-resolution spectroscopy, both with cross-correlation and single-line analyses, targeting key atomic and molecular species (e.g. He i, Hα, Na i, H2O, CO). We find a well-aligned orbit (λ = 2.7±1.1○) and vsin i⋆ = 4.5±0.1 km s−1, improving upon previous constraints. No significant atmospheric absorption is detected in either VIS or NIR data. Injection-and-recovery tests exclude an isothermal atmosphere with metallicity [M/H]≲ 10 ×[M/H]⊙ and simultaneously a grey cloud top pressure Pcloud ≳ 10 mbar, under the assumption of chemical equilibrium. WASP-13 b appears to belong to the class of low-density hot Jupiters with weak or featureless transmission spectra, most likely shaped by the presence of high-altitude clouds. Although a highly metal-enriched atmosphere cannot be fully excluded, current evidence disfavours this scenario. Further observations with next-generation facilities will be essential to characterise the atmospheric properties of this challenging target.
Related
- The GAPS Programme at TNG. LXXXI. The puzzle of the HeI absorption signal in the atmosphere of V1298Taub with GIARPS@TNG
- The GAPS Programme at TNG LXXXI. The puzzle of the HeI absorption signal in the atmosphere of V1298 Tau b with GIARPS@TNG
- GIARPS simultaneous optical and infrared high-spectral-resolution observations of Cepheids I. Limb darkening from cross-correlated radial velocities
- BeAR: The Bern Atmospheric Retrieval code - A GPU-accelerated framework for low-resolution, high-resolution, and joint retrievals of exoplanet atmospheres
- Optical design of VIPER: a high-resolution multimode fiber-fed VIPA spectrograph for characterizing exoplanet atmospheric escape
BibTeX
@article{sicilia2026gaps,
title = {{The GAPS programme at TNG LXXXII. The first atmospheric investigation of the gas giant WASP-13 b at high resolution with GIARPS}},
author = {D Sicilia and M Basilicata and G Guilluy and G Scandariato and F Borsa and C Di Maio and M Brogi and A Chiavassa and L Fossati and F Amadori and P Giacobbe and A S Bonomo and A Sozzetti and L Mancini and G Andreuzzi and S Colombo and V Fardella and A Ghedina and G Mantovan and G Piccinini},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = oct,
doi = {10.1093/mnras/stag1927},
url = {https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag1927/8907355},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The GAPS programme at TNG LXXXII. The first atmospheric investigation of the gas giant WASP-13 b at high resolution with GIARPS
AU - D Sicilia
AU - M Basilicata
AU - G Guilluy
AU - G Scandariato
AU - F Borsa
AU - C Di Maio
AU - M Brogi
AU - A Chiavassa
AU - L Fossati
AU - F Amadori
AU - P Giacobbe
AU - A S Bonomo
AU - A Sozzetti
AU - L Mancini
AU - G Andreuzzi
AU - S Colombo
AU - V Fardella
AU - A Ghedina
AU - G Mantovan
AU - G Piccinini
PY - 2026
DA - 2026/10/10
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag1927
UR - https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag1927/8907355
AB - Low-density transiting gas giant exoplanets are key benchmarks for atmospheric studies. Despite their large-scale heights, many of them remain poorly characterised. We present the first atmospheric investigation at high-resolution of the inflated (Rp~1.4 RJ), hot Jupiter (T~1500 K) WASP-13 b aiming at constraining its atmospheric composition and refine its orbital geometry. We analysed four transits observed with GIARPS at the TNG. Updated stellar and planetary parameters were re-derived from the most precise literature values, and a new Rossiter-McLaughlin analysis was performed to measure the projected spin-orbit angle (λ) and stellar rotational velocity (vsin i⋆). Atmospheric signals were searched using high-resolution spectroscopy, both with cross-correlation and single-line analyses, targeting key atomic and molecular species (e.g. He i, Hα, Na i, H2O, CO). We find a well-aligned orbit (λ = 2.7±1.1○) and vsin i⋆ = 4.5±0.1 km s−1, improving upon previous constraints. No significant atmospheric absorption is detected in either VIS or NIR data. Injection-and-recovery tests exclude an isothermal atmosphere with metallicity [M/H]≲ 10 ×[M/H]⊙ and simultaneously a grey cloud top pressure Pcloud ≳ 10 mbar, under the assumption of chemical equilibrium. WASP-13 b appears to belong to the class of low-density hot Jupiters with weak or featureless transmission spectra, most likely shaped by the presence of high-altitude clouds. Although a highly metal-enriched atmosphere cannot be fully excluded, current evidence disfavours this scenario. Further observations with next-generation facilities will be essential to characterise the atmospheric properties of this challenging target.
SN - 0035-8711
SN - 1365-2966
ER -