The 4.5 $\mu$m full-orbit phase curve of the hot Jupiter HD 209458b

Abstract

The hot Jupiter HD 209458b is particularly amenable to detailed study as it is among the brightest transiting exoplanet systems currently known (V-mag = 7.65; K-mag = 6.308) and has a large planet-to-star contrast ratio. HD 209458b is predicted to be in synchronous rotation about its host star with a hot spot that is shifted eastward of the substellar point by superrotating equatorial winds. Here we present the first full-orbit observations of HD 209458b, in which its 4.5 $\mu$m emission was recorded with $Spitzer$/IRAC. Our study revises the previous 4.5 $\mu$m measurement of HD 209458b's secondary eclipse emission downward by $\sim$35% to $0.1391$, changing our interpretation of the properties of its dayside atmosphere. We find that the hot spot on the planet's dayside is shifted eastward of the substellar point by $40.9^{\circ }\pm 6.0^{\circ }$, in agreement with circulation models predicting equatorial superrotation. HD 209458b's dayside (T${}_{bright}$ = 1499 $\pm$ 15 K) and nightside (T${}_{bright}$ = 972 $\pm$ 44 K) emission indicates a day-to-night brightness temperature contrast smaller than that observed for more highly irradiated exoplanets, suggesting that the day-to-night temperature contrast may be partially a function of the incident stellar radiation. The observed phase curve shape deviates modestly from global circulation model predictions potentially due to disequilibrium chemistry or deficiencies in the current hot CH${}_4$ line lists used in these models. Observations of the phase curve at additional wavelengths are needed in order to determine the possible presence and spatial extent of a dayside temperature inversion, as well as to improve our overall understanding of this planet's atmospheric circulation.

10 pages, 6 figures, 3 tables, published in ApJ

References in corpus (23)

• Improved parameters for extrasolar transiting planets
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Can TiO Explain Thermal Inversions in the Upper Atmospheres of Irradiated Giant Planets?
• The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b
• Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands
• Multi-Wavelength Constraints on the Day-Night Circulation Patterns of HD 189733b
• The phase-dependent Infrared brightness of the extrasolar planet upsilon Andromedae b
• Dynamics and Disequilibrium Carbon Chemistry in Hot Jupiter Atmospheres, With Application to HD 209458b
• Atmospheric Circulation of Hot Jupiters: Three-dimensional circulation models of HD 209458b and HD 189733b with Simplified Forcing
• A Spectrum of an Extrasolar Planet
• The Very Low Albedo of an Extrasolar Planet: MOST Spacebased Photometry of HD 209458
• Inverting Phase Functions to Map Exoplanets
• Atmospheric Circulation of Hot Jupiters: A Shallow Three-Dimensional Model
• Atmospheric Dynamics of Short-period Extra Solar Gas Giant Planets I: Dependence of Night-Side Temperature on Opacity
• Atmospheric Circulation of Eccentric Hot Neptune GJ436b
• Hot Nights on Extrasolar Planets: Mid-IR Phase Variations of Hot Jupiters
• TiO and VO broad band absorption features in the optical spectrum of the atmosphere of the hot-Jupiter HD209458b
• High accuracy transit photometry of the planet OGLE-TR-113b with a new deconvolution-based method
• Transiting planets - lightcurve analysis for eccentric orbits
• Hydrodynamic Simulations of Unevenly Irradiated Jovian Planets
• The mid-infrared spectrum of the transiting exoplanet HD 209458b
• A Hubble Space Telescope transit light curve for GJ436b

Cited by in corpus (74)

• Spitzer Secondary Eclipses of the Dense, Modestly-irradiated, Giant Exoplanet HAT-P-20b Using Pixel-Level Decorrelation
• Changing Phases of Alien Worlds: Probing Atmospheres of Kepler Planets with High-Precision Photometry
• Atmospheric Dynamics of Hot Exoplanets
• Spitzer Phase Curve Constraints for WASP-43b at 3.6 and 4.5 microns
• The Effects of Consistent Chemical Kinetics Calculations on the Pressure-Temperature Profiles and Emission Spectra of Hot Jupiters
• High-Resolution Spectroscopic Detection of TiO and Stratosphere in the Day-side of WASP-33b
• New Analysis Indicates No Thermal Inversion in the Atmosphere of HD 209458b
• Balancing the Energy Budget of Short-Period Giant Planets: Evidence for Reflective Clouds and Optical Absorbers
• Forward and Inverse Modeling of the Emission and Transmission Spectrum of GJ 436b: Investigating Metal Enrichment, Tidal Heating, and Clouds
• The Atmospheric Circulation of Ultra-hot Jupiters
• On Correlated-noise Analyses Applied To Exoplanet Light Curves
• Transit spectroscopy with JWST: Systematics, starspots and stitching
• Magnetic Effects in Hot Jupiter Atmospheres
• A search for TiO in the optical high-resolution transmission spectrum of HD 209458b: Hindrance due to inaccuracies in the line database
• Hot Jupiters: Origins, Structure, Atmospheres
• Atmospheric Dynamics of Hot Giant Planets and Brown Dwarfs
• Aerosols in Exoplanet Atmospheres
• WASP-80b has a dayside within the T-dwarf range
• The UK Met Office GCM with a sophisticated radiation scheme applied to the hot Jupiter HD 209458b
• A Semi-Analytical Model of Visible-Wavelength Phase Curves of Exoplanets and Applications to Kepler-7 b and Kepler-10 b
• Non-detection of TiO and VO in the atmosphere of WASP-121b using high-resolution spectroscopy
• Evidence against a strong thermal inversion in HD 209458 b from high-dispersion spectroscopy
• Detection of a Westward Hotspot Offset in the Atmosphere of a Hot Gas Giant CoRoT-2b
• A temperature inversion with atomic iron in the ultra-hot dayside atmosphere of WASP-189b
• A Significant Increase in Detection of High-Resolution Emission Spectra Using a Three-Dimensional Atmospheric Model of a Hot Jupiter
• A Comprehensive Reanalysis of $\text{Spitzer}$'s 4.5 $\mu$m Phase Curves, and the Phase Variations of the Ultra-hot Jupiters MASCARA-1b and KELT-16b
• Observability of signatures of transport-induced chemistry in clear atmospheres of hot gas giant exoplanets
• Phase Offsets and the Energy Budgets of Hot Jupiters
• Overcast on Osiris: 3D radiative-hydrodynamical simulations of a cloudy hot Jupiter using the parameterised, phase-equilibrium cloud formation code EddySed
• Lava Worlds: From Early Earth to Exoplanets
• CHEOPS geometric albedo of the hot Jupiter HD 209458b
• The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs
• KELT-16b: A highly irradiated, ultra-short period hot Jupiter nearing tidal disruption
• Constraining Hot Jupiter Atmospheric Structure and Dynamics through Doppler Shifted Emission Spectra
• Impact of photochemical hazes and gases on exoplanet atmospheric thermal structure
• An independent analysis of the Spitzer/IRAC phase curves of WASP43 b
• The Pale Green Dot: A Method to Characterize Proxima Centauri b using Exo-Aurorae
• The ground-based H, K, and L-band absolute emission spectra of HD 209458b
• The Impact of Mixing Treatments on Cloud Modelling in 3D Simulations of Hot Jupiters
• Extremely long convergence times in a 3D GCM simulation of the sub-Neptune Gliese 1214b
• Phase Curves of Hot Neptune LTT 9779b Suggest a High-Metallicity Atmosphere
• A New Analysis of 8 Spitzer Phase Curves and Hot Jupiter Population Trends: Qatar-1b, Qatar-2b, WASP-52b, WASP-34b, and WASP-140b
• JWST Transit Spectra I: Exploring Potential Biases and Opportunities in Retrievals of Tidally-locked Hot Jupiters with Clouds and Hazes
• An exploration of model degeneracies with a unified phase curve retrieval analysis: The light and dark sides of WASP-43 b
• Search for TiO and Optical Night-side Emission from the Exoplanet WASP-33b
• Phase curve pollution of exoplanet transmission spectra
• Modons on Tidally Synchronised Extrasolar Planets
• Broadband transmission spectroscopy of HD209458b with ESPRESSO: Evidence for Na, TiO, or both
• TauREx3 PhaseCurve: A 1.5D model for phase curve description
• Ionization and transport in partially ionized multicomponent plasmas: Application to atmospheres of hot Jupiters
• The Acceleration of Superrotation in Simulated Hot Jupiter Atmospheres
• Smaller than expected bright-spot offsets in Spitzer phase curves of the hot Jupiter Qatar-1b
• Spitzer IRAC observations of JWST calibration stars
• HST/WFC3 Complete Phase-resolved Spectroscopy of White Dwarf-Brown Dwarf Binaries WD 0137 and EPIC 2122
• Coupled Day-Night Models of Exoplanetary Atmospheres
• Mapping the pressure-dependent day-night temperature contrast of a strongly irradiated atmosphere with HST spectroscopic phase curve
• Phase Shift of Planetary Waves and Wave--Jet Resonance on Tidally Locked Planets
• Colour-magnitude diagrams of transiting Exoplanets -- III. A public code, nine strange planets, and the role of Phosphine
• Thermal Phase Curves of XO-3b: an Eccentric Hot Jupiter at the Deuterium Burning Limit
• Hot exoplanetary atmospheres in 3D
• Phase curve and variability analysis of WASP-12b using TESS photometry
• Atmospheric Characterization via Broadband Color Filters on the PLAnetary Transits and Oscillations of stars (PLATO) Mission
• SPORK That Spectrum: Increasing Detection Significances from High-Resolution Exoplanet Spectroscopy with Novel Smoothing Algorithms
• Modeling the Thermal Bulge of A Hot Jupiter with the Two-Stream Approximation
• The bright side of the light curve: a general photometric model of non-transiting exorings
• Hotter Than Expected: HST/WFC3 Phase-resolved Spectroscopy of a Rare Irradiated Brown Dwarf with Strong Internal Heat Flux
• The strange case of Na I in the atmosphere of HD209458 b: Reconciling low- and high-resolution spectroscopic observations G
• Reflected-light Phase Curves with PICASO: A Kepler-7b Case Study
• Oceanic Superrotation on Tidally Locked Planets
• The dark days are overcast: Iron-bearing clouds on HD 209458 b and WASP-43 b can explain low dayside albedos
• Examining the detectability of ringing on highly eccentric exoplanets
• Effective drag in rotating, poorly conducting plasma turbulence
• Day-side Fe I Emission, Day-Night Brightness Contrast and Phase Offset of the Exoplanet WASP-33b
• Cloudy and Cloud-free Thermal Phase Curves with PICASO: Applications to WASP-43b