Detection of the tidal deformation of WASP-103b at $3\sigma$ with CHEOPS

Abstract

WASP-103b is the exoplanet with the highest expected deformation signature in its transit light curve and one of the shortest expected spiral-in times. Measuring the tidal deformation of the planet would allow us to estimate the second degree fluid Love number and gain insight into the planet's internal structure. Moreover, measuring the tidal decay timescale would allow us to estimate the stellar tidal quality factor, which is key to constraining stellar physics. We obtained 12 transit light curves of WASP-103b with the CHEOPS to estimate the tidal deformation and tidal decay of this extreme system. We modelled the high-precision CHEOPS transit light curves together with systematic instrumental noise using multi-dimensional Gaussian process regression informed by a set of instrumental parameters. To model the tidal deformation, we used a parametrisation model which allowed us to determine the second degree fluid Love number of the planet. We combined our light curves with previously observed transits of WASP-103b with HST and Spitzer. We estimate the radial Love number of WASP-103b to be $h_f=1.59_{-0.53}^{+0.45}$. This is the first time that the tidal deformation is directly detected (at $3\sigma$) from the transit light curve of an exoplanet. Combining the transit times derived from CHEOPS, with the other transit times available in the literature, we find no significant orbital period variation for WASP-103b. However, the data show a hint of an orbital period increase instead of a decrease, as is expected for tidal decay. This could be either due to a visual companion star if this star is bound, the Applegate effect, or a statistical artefact. The estimated Love number of WASP-103b is similar to Jupiter's. This will allow us to constrain the internal structure and composition of WASP-103b, which could provide clues on the inflation of hot Jupiters. (Abridged)

21 pages, 9 figures, 11 tables, CHEOPS light curves available online, Published A&A

References in corpus (36)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
• The CHEOPS mission
• Limb darkening and exoplanets: testing stellar model atmospheres and identifying biases in transit parameters
• Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited
• CLES, Code Liegeois d'Evolution Stellaire
• PASTIS: Bayesian extrasolar planet validation. I. General framework, models, and performance
• The Orbit of WASP-12b is Decaying
• 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 effect of stellar limb darkening values on the accuracy of the planet radii derived from photometric transit observations
• A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b
• High-resolution imaging of $Kepler$ planet host candidates. A comprehensive comparison of different techniques
• Revising the ages of planet-hosting stars
• Warm terrestrial planet with half the mass of Venus transiting a nearby star
• CHEOPS observations of the HD 108236 planetary system: A fifth planet, improved ephemerides, and planetary radii
• WASP-4b Arrived Early for the TESS Mission
• WASP-186 and WASP-187: two hot Jupiters discovered by SuperWASP and SOPHIE with additional observations by TESS
• On the equilibrium figure of close-in planets and satellites
• High-precision photometry by telescope defocussing. VII. The ultra-short period planet WASP-103
• Reinvestigating $\alpha$ Cen AB in light of asteroseismic forward and inverse methods
• Transit light curve and inner structure of close-in planets
• Investigating the physical properties of transiting hot Jupiters with the 1.5-m Kuiper Telescope
• Improving transit characterisation with Gaussian process modelling of stellar variability
• Machine learning inference of the interior structure of low-mass exoplanets
• Near-Infrared Emission Spectrum of WASP-103b using Hubble Space Telescope/Wide Field Camera 3
• An estimate of the $k_2$ Love number of WASP-18Ab from its radial velocity measurements
• Tidally Distorted Exoplanets: Density Corrections for Short-Period Hot-Jupiters based solely on Observable Parameters
• Detectability of shape deformation in short-period exoplanets
• High-precision multi-wavelength eclipse photometry of the ultra-hot gas giant exoplanet WASP-103 b
• Retrieval of the fluid Love number $k_2$ in exoplanetary transit curves
• A comparative study of WASP-67b and HAT-P-38b from WFC3 data
• MCMCI: A code to fully characterise an exoplanetary system
• Ground-based photometry of the 21-day Neptune HD106315c
• Probing TRAPPIST-1-like systems with K2

Cited by in corpus (29)

• TESS Revisits WASP-12: Updated Orbital Decay Rate and Constraints on Atmospheric Variability
• HD 23472: A multi-planetary system with three super-Earths and two potential super-Mercuries
• Examining the orbital decay targets KELT-9 b, KELT-16 b and WASP-4 b, and the transit-timing variations of HD 97658 b
• TOI-5678 b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS
• GASTLI: An open-source coupled interior-atmosphere model to unveil gas giant composition
• CHEOPS finds KELT-1b darker than expected in visible light: Discrepancy between the CHEOPS and TESS eclipse depths
• The young mini-Neptune HD 207496b that is either a naked core or on the verge of becoming one
• Measuring the orbit shrinkage rate of hot Jupiters due to tides
• TASTE V. A new ground-based investigation of orbital decay in the ultra-hot Jupiter WASP-12b
• Tidal dissipation due to the elliptical instability and turbulent viscosity in convection zones in rotating giant planets and stars
• Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
• Searching for Candidates of Orbital Decays among Transit Exoplanets
• Evidence of apsidal motion and a possible co-moving companion star detected in the WASP-19 system
• Planet-star interactions with precise transit timing. III. Entering the regime of dynamical tides
• A close outer companion to the ultra-hot Jupiter TOI-2109 b?
• Assessing the processes behind planet engulfment and its imprints
• Thermal Emission from the hot Jupiter WASP-103b in J and Ks Bands
• Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emission
• The phase curve of the ultra-hot Jupiter WASP-167b as seen by TESS
• A CHEOPS Search for Massive, Long-Period Companions to the Warm Jupiter K2-139 b
• Relationship between the moment of inertia and the $k_2$ Love number of fluid extra-solar planets
• Retrieving interior properties of hot Jupiters with Love numbers and atmospheric measurements
• Tidal Distortions as a Bottleneck on Constraining Exoplanet Compositions
• Exo-Geoscience Perspectives Beyond Habitability
• Exploring Exoplanet Dynamics with JWST: Tides, Rotation, Rings, and Moons
• Yuti: A General-purpose Transit Simulator for Arbitrary Shaped Objects Orbiting Stars
• Ground-Based Reconnaissance Observations of 21 Exoplanet Atmospheres with the Exoplanet Transmission Spectroscopy Imager
• Exploring the habitability and interior composition of exoplanets lying within the extended habitable zone
• The tidal quality of the hot Jupiter WASP-12b