Thermal emission spectra of the ultra-hot Jupiter WASP-33 b

Abstract

Observations of exoplanetary atmospheres provide critical insights into their chemical composition, formation and evolution history. Ultra-hot Jupiters serve as excellent targets for atmospheric characterization; studies of these planets may yield key understanding of gas giant's formation and evolution history. We present a thermal emission study of WASP-33 b's dayside atmosphere, based on two secondary eclipse observations with CFHT/WIRCam in two specific narrow band filters, namely the CO and CH4${}_{\mathrm{on}}$ filters, and archival data with HST/WFC3 and Spitzer. Stellar pulsations of the host star induce some quasi-periodic photometric variations, particularly in the CH4${}_{\mathrm{on}}$ band, which are modelled and corrected in the high-precision differential light curves. An eclipse depth of $1565.2_{-237.5}^{+228.6}$ ppm and $914.3_{-57.0}^{+56.1}$ ppm is determined for the CO and CH4${}_{\mathrm{on}}$ bands, respectively. Combined with HST/WFC3 and Spitzer data, our joint retrieval of WASP-33 b's dayside atmosphere reveals a high metallicity ([Fe/H] $=1.52_{-0.52}^{+0.35}$), high C/O ratio (C/O $=0.78_{-0.04}^{+0.03}$), and a thermal inversion layer, suggesting a formation history involving metal-rich gas accretion. We confirm the presence of the molecules H${}_2$O, H${}^{-}$ and CO, and report a tentative detection of TiO in the dayside atmosphere of WASP-33 b. Future higher precision observations with JWST may provide better understand constraints on the chemical abundances of oxygen and refractory element abundances to better WASP-33 b's formation and evolutionary pathway.

Accepted for publication in Astronomy and Astrophysics(12 pages, 16 figures, 5 tables). Language editor corrected version

References in corpus (36)

• petitRADTRANS: a Python radiative transfer package for exoplanet characterization and retrieval
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host
• Chemical enrichment of giant planets and discs due to pebble drift
• A hybrid line list for CH${}_4$ and hot methane continuum
• High-Resolution Spectroscopic Detection of TiO and Stratosphere in the Day-side of WASP-33b
• Friends of Hot Jupiters. IV. Stellar companions beyond 50 AU might facilitate giant planet formation, but most are unlikely to cause Kozai-Lidov migration
• The hot dayside and asymmetric transit of WASP-189b seen by CHEOPS
• Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b
• Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse
• First Detection of Hydroxyl Radical Emission from an Exoplanet Atmosphere: High-dispersion Characterization of WASP-33b using Subaru/IRD
• Detection of Fe and evidence for TiO in the dayside emission spectrum of WASP-33b
• Retrieval survey of metals in six ultra-hot Jupiters: Trends in chemistry, rain-out, ionisation and atmospheric dynamics
• Near-infrared Thermal Emission Detections of a number of hot Jupiters and the Systematics of Ground-based Near-infrared Photometry
• A transition between the hot and the ultra-hot Jupiter atmospheres
• Detection of Fe\,{\sc i} Emission in the Day-side Spectrum of WASP-33b
• Connecting planet formation and astrochemistry: Refractory carbon depletion leading to super-stellar C/O in giant planetary atmospheres
• Carbon monoxide emission lines reveal an inverted atmosphere in the ultra hot Jupiter WASP-33 b consistent with an eastward hot spot
• TESS unveils the phase curve of WASP-33b. Characterization of the planetary atmosphere and the pulsations from the star
• Precise photometric transit follow-up observations of five close-in exoplanets : update on their physical properties
• Atmospheric retrievals with petitRADTRANS
• High-resolution transmission spectroscopy study of ultra-hot Jupiters HAT-P-57b, KELT-17b, KELT-21b, KELT-7b, MASCARA-1b, and WASP-189b
• Detection of the hydrogen Balmer lines in the ultra-hot Jupiter WASP-33b
• Atmospheric characterization of the ultra-hot Jupiter WASP-33b: Detection of Ti and V emission lines and retrieval of a broadened line profile
• Detection of CO emission lines in the dayside atmospheres of WASP-33b and WASP-189b with GIANO
• Keck/KPIC Emission Spectroscopy of WASP-33b
• The carbon-to-oxygen ratio: implications for the spectra of hydrogen-dominated exoplanet atmospheres
• The GROUSE project III: Ks-band observations of the thermal emission from WASP-33b
• Silicon in the dayside atmospheres of two ultra-hot Jupiters
• Is TiO emission present in the ultra-hot Jupiter WASP-33b? A reassessment using the improved ExoMol Toto line list
• Search for TiO and Optical Night-side Emission from the Exoplanet WASP-33b
• The obliquity and atmosphere of the ultra-hot Jupiter TOI-1431b (MASCARA-5b): A misaligned orbit and no signs of atomic ormolecular absorptions
• Nodal Precession and Tidal Evolution of Two Hot-Jupiters: WASP-33 b and KELT-9 b
• Nodal Precession of WASP-33b for Eleven Years by Doppler Tomographic and Transit Photometric Observations
• Thermal Emission from the hot Jupiter WASP-103b in J and Ks Bands
• Cleaning WASP-33 b transits from the host star photometric variability: analysis of TESS data from two sectors