Detection of Ionized Calcium in the Atmosphere of the Ultra-Hot Jupiter WASP-76b

Abstract

Recent observations of the ultra-hot Jupiter WASP-76b have revealed a diversity of atmospheric species. Here we present new high-resolution transit spectroscopy of WASP-76b with GRACES at the Gemini North Observatory, serving as a baseline for the Large and Long Program "Exploring the Diversity of Exoplanet Atmospheres at High Spectral Resolution" (Exoplanets with Gemini Spectroscopy, or ExoGemS for short). With a broad spectral range of $400-1050$ nm, these observations allow us to search for a suite of atomic species. We recover absorption features due to neutral sodium (Na I), and report a new detection of the ionized calcium (Ca II) triplet at ~ $850$ nm in the atmosphere of WASP-76b, complementing a previous detection of the Ca II H & K lines. The triplet has line depths of $0.295\pm 0.034$% at ~ $849.2$ nm, $0.574\pm 0.041$% at ~ $854.2$ nm, and $0.454\pm 0.024$% at ~ $866.2$ nm, corresponding to effective radii close to (but within) the planet's Roche radius. These measured line depths are significantly larger than those predicted by model LTE and NLTE spectra obtained on the basis of a pressure-temperature profile computed assuming radiative equilibrium. The discrepancy suggests that the layers probed by our observations are either significantly hotter than predicted by radiative equilibrium and/or in a hydrodynamic state. Our results shed light on the exotic atmosphere of this ultra-hot world, and will inform future analyses from the ExoGemS survey.

19 pages, 10 figures, 3 tables. Accepted for publication in Astrophysical Journal Letters

References in corpus (29)

• Array Programming with NumPy
• ESPRESSO@VLT -- On-sky performance and first results
• Sodium Absorption From the Exoplanetary Atmosphere of HD189733b Detected in the Optical Transmission Spectrum
• The fast spin-rotation of a young extrasolar planet
• Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph
• Nightside condensation of iron in an ultra-hot giant exoplanet
• Ground-based detection of sodium in the transmission spectrum of exoplanet HD209458b
• Synthetic Spectra and Colors of Young Giant Planet Atmospheres: Effects of Initial Conditions and Atmospheric Metallicity
• Barycentric Corrections at 1 cm/s for precise Doppler velocities
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) - II. A broadened sodium feature on the ultra-hot giant WASP-76b
• Beyond Equilibrium Temperature: How the Atmosphere/Interior Connection Affects the Onset of Methane, Ammonia, and Clouds in Warm Transiting Giant Planets
• Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b
• ESPRESSO high resolution transmission spectroscopy of WASP-76b
• Decomposing the Iron Cross-Correlation Signal of the Ultra-Hot Jupiter WASP-76b in Transmission using 3D Monte-Carlo Radiative Transfer
• Search for water vapor in the high-resolution transmission spectrum of HD189733b in the visible
• Searching for Thermal Inversion Agents in the Transmission Spectrum of MASCARA-2b/KELT-20b: Detection of Neutral Iron and Ionised Calcium H$\&$K Lines
• Detection of ionized calcium in the atmosphere of the ultra-hot Jupiter KELT-9b
• Confirmation of Asymmetric Iron Absorption in WASP-76b with HARPS
• An inventory of atomic species in the atmosphere of WASP-121b using UVES high-resolution spectroscopy
• Into the Storm: Diving into the winds of the ultra hot Jupiter WASP-76 b with HARPS and ESPRESSO
• Non-local thermodynamic equilibrium effects determine the upper atmospheric temperature structure of the ultra-hot Jupiter KELT-9b
• Rapid escape of ultra-hot exoplanet atmospheres driven by Hydrogen Balmer absorption
• WASP-127b: A misaligned planet with a partly cloudy atmosphere and tenuous sodium signature seen by ESPRESSO
• Prospects for Characterizing the Haziest Sub-Neptune Exoplanets with High Resolution Spectroscopy
• A data-driven approach to constraining the atmospheric temperature structure of KELT-9b
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) V. Detection of sodium on the bloated super-Neptune WASP-166b
• GRACES: Gemini remote access to CFHT ESPaDOnS Spectrograph through the longest astronomical fiber ever made (Experimental phase completed.)
• HST/STIS transmission spectrum of the ultra-hot Jupiter WASP-76 b confirms the presence of sodium in its atmosphere
• Non-Local Thermodynamic Equilibrium Transmission Spectrum Modelling of HD209458b

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• Magnetic Drag and 3-D Effects in Theoretical High-Resolution Emission Spectra of Ultrahot Jupiters: the Case of WASP-76b
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