Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) VII. Detection of sodium on the long-transiting inflated sub-Saturn KELT-11 b

Abstract

KELT-11b is an inflated sub-Saturn with a hot atmosphere and that orbits a bright evolved subgiant star, making it a prime choice for atmospheric characterization, but that transits its host star for more than seven hours. We observed this system in series of three consecutive nights with the HARPS spectrograph and report on the analysis of the transmission spectrum obtained from this dataset. Our results highlight the potential for independent observations of a long-transiting planet over consecutive nights. Our study reveals a sodium excess absorption of $0.28\pm 0.05$ and $0.50\pm 0.06$ in the Na D1 and D2 lines, respectively. This corresponds to 1.44 and 1.69 times the white-light planet radius in the line cores. Wind pattern modeling tends to prefer day-to-night side winds with no vertical winds, which is surprising considering the planet bloatedness. The modeling of the Rossiter-Mclaughlin effect yields a significantly misaligned orbit, with a projected spin-orbit angle of $\lambda =-77.86_{-2.26}^{+2.36}{}^{\circ }$. The characteristics of KELT-11 b, notably its extreme scale height and long transit, make it an ideal and unique target for next-generation telescopes. Our results as well as recent findings from HST, TESS, and CHEOPS observations could make KELT-11 b a benchmark exoplanet in atmospheric characterization.

19 pages, 18 figures, 8 tables. Accepted for publication in Astronomy & Astrophysics

References in corpus (33)

• The Gaia mission
• Bayes in the sky: Bayesian inference and model selection in cosmology
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• Sodium Absorption From the Exoplanetary Atmosphere of HD189733b Detected in the Optical Transmission Spectrum
• Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph
• Ground-based detection of sodium in the transmission spectrum of exoplanet HD209458b
• Mass-Metallicity Trends in Transiting Exoplanets from Atmospheric Abundances of H${}_2$O, Na, and K
• PASTIS: Bayesian extrasolar planet validation. I. General framework, models, and performance
• Detection of titanium oxide in the atmosphere of a hot Jupiter
• Stellar obliquities in exoplanetary systems
• The Complete transmission spectrum of WASP-39b with a precise water constraint
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) IV. A spectral inventory of atoms and molecules in the high-resolution transmission spectrum of WASP-121 b
• Orbital misalignment of the Neptune-mass exoplanet GJ 436b with the spin of its cool star
• Atmospheric Rossiter-McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO
• Magnetic field strengths of hot Jupiters from signals of star-planet interactions
• High-resolution confirmation of an extended helium atmosphere around WASP-107b
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) - II. A broadened sodium feature on the ultra-hot giant WASP-76b
• Detection of sodium in the atmosphere of WASP-69b
• ESPRESSO high resolution transmission spectroscopy of WASP-76b
• Mass loss rate and local thermodynamic state of KELT-9 b thermosphere from the hydrogen Balmer series
• Search for water vapor in the high-resolution transmission spectrum of HD189733b in the visible
• From dense hot Jupiter to low-density Neptune: The discovery of WASP-127b, WASP-136b and WASP-138b
• Wind of Change: retrieving exoplanet atmospheric winds from high-resolution spectroscopy
• The atmosphere of HD 209458b seen with ESPRESSO. No detectable planetary absorptions at high resolution
• Into the Storm: Diving into the winds of the ultra hot Jupiter WASP-76 b with HARPS and ESPRESSO
• WASP-127b: A misaligned planet with a partly cloudy atmosphere and tenuous sodium signature seen by ESPRESSO
• Refined architecture of the WASP-8 system: a cautionary tale for traditional Rossiter-McLaughlin analysis
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) VI. Non-detection of sodium with HARPS on the bloated super-Neptune WASP-127b
• Probing the atmosphere of WASP-69 b with low- and high-resolution transmission spectroscopy
• Assessing telluric correction methods for Na detections with high-resolution exoplanet transmission spectroscopy
• The Hot Neptune WASP-166 b with ESPRESSO II: Confirmation of atmospheric sodium

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