The 8 Micron Phase Variation of the Hot Saturn HD 149026b

Abstract

We monitor the star HD 149026 and its Saturn-mass planet at 8.0 micron over slightly more than half an orbit using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We find an increase of 0.0227% +/- 0.0066% (3.4 sigma significance) in the combined planet-star flux during this interval. The minimum flux from the planet is 45% +/- 19% of the maximum planet flux, corresponding to a difference in brightness temperature of 480 +/- 140 K between the two hemispheres. We derive a new secondary eclipse depth of 0.0411% +/- 0.0076% in this band, corresponding to a dayside brightness temperature of 1440 +/- 150 K. Our new secondary eclipse depth is half that of a previous measurement (3.0 sigma difference) in this same bandpass by Harrington et al. (2007). We re-fit the Harrington et al. (2007) data and obtain a comparably good fit with a smaller eclipse depth that is consistent with our new value. In contrast to earlier claims, our new eclipse depth suggests that this planet's dayside emission spectrum is relatively cool, with an 8 micron brightness temperature that is less than the maximum planet-wide equilibrium temperature. We measure the interval between the transit and secondary eclipse and find that that the secondary eclipse occurs 20.9 +7.2 / -6.5 minutes earlier (2.9 sigma) than predicted for a circular orbit, a marginally significant result. This corresponds to e*cos(omega) = -0.0079 +0.0027 / -0.0025 where e is the planet's orbital eccentricity and omega is the argument of pericenter.

17 pages, 12 figure, accepted for publication in ApJ

References in corpus (33)

• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• Detection of Thermal Emission from an Extrasolar Planet
• Can TiO Explain Thermal Inversions in the Upper Atmospheres of Irradiated Giant Planets?
• Atmospheric Sulfur Photochemistry on Hot Jupiters
• The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b
• Strong Water Absorption in the Dayside Emission Spectrum of the Planet HD 189733b
• Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
• 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
• Strong Infrared Emission from the Extrasolar Planet HD189733b
• 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
• Spitzer Transit and Secondary Eclipse Photometry of GJ 436b
• Inverting Phase Functions to Map Exoplanets
• The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733
• XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary
• 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
• Hot Nights on Extrasolar Planets: Mid-IR Phase Variations of Hot Jupiters
• The Transit Light Curve Project. III. Tres Transits of TrES-1
• Thermal Emission of Exoplanet XO-1b
• On the Origin of HD149026b
• The Rotation Period of the Planet-Hosting Star HD 189733
• Optical Albedo Theory of Strongly-Irradiated Giant Planets: The Case of HD 209458b
• Hydrodynamic Simulations of Unevenly Irradiated Jovian Planets
• Transit Photometry of the Core-Dominated Planet HD 149026b
• A Precise Estimate of the Radius of the Exoplanet HD 149026b from Spitzer Photometry
• Five New Transits of the Super-Neptune HD 149026
• On Signatures of Atmospheric Features in Thermal Phase Curves of Hot Jupiters
• The formation of HD 149026 b

Cited by in corpus (99)

• EXOFAST: A fast exoplanetary fitting suite in IDL
• Exoplanet Atmospheres
• Characterizing transiting exoplanet atmospheres with JWST
• The Statistics of Albedo and Heat Recirculation on Hot Exoplanets
• Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
• 3.6 and 4.5 Micron Phase Curves and Evidence for Non-Equilibrium Chemistry in the Atmosphere of Extrasolar Planet HD 189733b
• PandExo: A Community Tool for Transiting Exoplanet Science with JWST & HST
• Rotation and winds of exoplanet HD 189733 b measured with high-dispersion transmission spectroscopy
• The Influence of Non-Uniform Cloud Cover on Transit Transmission Spectra
• Exoplanetary Atmospheres - Chemistry, Formation Conditions, and Habitability
• Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences
• Atmospheric Heat Redistribution on Hot Jupiters
• Orbital Phase Variations of the Eccentric Giant Planet HAT-P-2b
• A Two-Dimensional Infrared Map of the Extrasolar Planet HD 189733b
• Atmospheric Dynamics of Hot Exoplanets
• Simulating the escaping atmospheres of hot gas planets in the solar neighborhood
• The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet
• Transit and Eclipse Analyses of Exoplanet HD 149026b Using BLISS Mapping
• The 4.5 $\mu$m full-orbit phase curve of the hot Jupiter HD 209458b
• Pseudo 2D chemical model of hot Jupiter atmospheres: application to HD 209458b and HD 189733b
• Detection of molecular absorption in the dayside of exoplanet 51 Pegasi b?
• Balancing the Energy Budget of Short-Period Giant Planets: Evidence for Reflective Clouds and Optical Absorbers
• On the Orbit of Exoplanet WASP-12b
• The Atmospheric Circulation of Ultra-hot Jupiters
• On Correlated-noise Analyses Applied To Exoplanet Light Curves
• A Spitzer Transmission Spectrum for the Exoplanet GJ 436b, Evidence for Stellar Variability, and Constraints on Dayside Flux Variations
• Magnetic Scaling Laws for the Atmospheres of Hot Giant Exoplanets
• Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences. II. Comparison with Observations
• Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System
• A Detection Of H-alpha In An Exoplanetary Exosphere
• The Transiting Exoplanet Community Early Release Science Program for JWST
• Spitzer observations of the thermal emission from WASP-43b
• Magnetohydrodynamic Simulations of the Atmosphere of HD 209458b
• Studying the atmosphere of the exoplanet HAT-P-7b via secondary eclipse measurements with EPOXI, Spitzer and Kepler
• Thermal phase curves of nontransiting terrestrial exoplanets 1. Characterizing atmospheres
• Spectra as Windows into Exoplanet Atmospheres
• 3.6 and 4.5 $\mu$m Phase Curves of the Highly-Irradiated Eccentric Hot Jupiter WASP-14b
• Phase curves of WASP-33b and HD 149026b and a New Correlation Between Phase Curve Offset and Irradiation Temperature
• Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program
• Spitzer Secondary Eclipses of WASP-18b
• Highlights in the Study of Exoplanet Atmospheres
• Features in the Broadband Eclipse Spectra of Exoplanets: Signal or Noise?
• Studying atmosphere-dominated hot Jupiter Kepler phase curves: Evidence that inhomogeneous atmospheric reflection is common
• A Semi-Analytical Model of Visible-Wavelength Phase Curves of Exoplanets and Applications to Kepler-7 b and Kepler-10 b
• The astrophysics of visible-light orbital phase curves in the space age
• Vertical Tracer Mixing in Hot Jupiter Atmospheres
• WASP-8b: Characterization of a Cool and Eccentric Exoplanet with Spitzer
• Evidence for a spectroscopic direct detection of reflected light from 51 Peg b
• Spitzer/MIPS 24 micron Observations of HD 209458b: 3 eclipses, 2.5 transits, and a Phase Curve Corrupted by Instrumental Sensitivity Variations
• A Survey of Alkali Line Absorption in Exoplanetary Atmospheres
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
• SOPHIE velocimetry of Kepler transit candidates IX. KOI-415 b: a long-period, eccentric transiting brown dwarf to an evolved Sun
• Thermal Emission of WASP-14b Revealed with Three Spitzer Eclipses
• Mass Loss from the Exoplanet WASP-12b Inferred from $\text{Spitzer}$ Phase Curves
• 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
• Thermal emission at 3.6-8 micron from WASP-19b: a hot Jupiter without a stratosphere orbiting an active star
• Secondary eclipse observations for seven hot-Jupiters from the Anglo-Australian Telescope
• Phase Offsets and the Energy Budgets of Hot Jupiters
• On the Eccentricity Distribution of Short-Period Single-Planet Systems
• Improved parameters of seven Kepler giant companions characterized with SOPHIE and HARPS-N
• Thermal Emission and Tidal Heating of the Heavy and Eccentric Planet XO-3b
• Origins Space Telescope Mission Concept Study Report
• The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs
• Spectroscopic time series performance of the Mid-Infrared Instrument on the JWST
• Photometric Phase Variations of Long-Period Eccentric Planets
• The EVIL-MC Model for Ellipsoidal Variations of Planet-Hosting Stars and Applications to the HAT-P-7 System
• The Implications of M Dwarf Flares on the Detection and Characterization of Exoplanets at Infrared Wavelengths
• Ground-based detections of thermal emission from the dense hot Jupiter WASP-43b in H and Ks-bands
• A More Informative Map: Inverting Thermal Orbital Phase and Eclipse Lightcurves of Exoplanets
• The hottest hot Jupiters may host Atmospheric Dynamos
• Colour-Magnitude Diagrams of Transiting Exoplanets. I - Systems with parallaxes
• 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
• On the Inclination Dependence of Exoplanet Phase Signatures
• Spitzer IRAC Sparsely Sampled Phase Curve of the Exoplanet WASP-14b
• Detectability of Exoplanet Periastron Passage in the Infra-Red
• Revised Orbit and Transit Exclusion for HD 114762b
• Characterization of the Kepler-101 planetary system with HARPS-N. A hot super-Neptune with an Earth-sized low-mass companion
• Investigating the detectability of hydrocarbons in exoplanet atmospheres with JWST
• Characterization of Exoplanets: Secondary Eclipses
• Improved Orbital Parameters and Transit Monitoring for HD 156846b
• Planetary Phase Variations of the 55 Cancri System
• Signatures of Obliquity in Thermal Phase Curves of Hot Jupiters
• Exoplanetary Geophysics -- An Emerging Discipline
• Coupled Day-Night Models of Exoplanetary Atmospheres
• Cyclic Transit Probabilities of Long-Period Eccentric Planets Due to Periastron Precession
• Photometric precision of a Si:As impurity band conduction mid-infrared detector and application to transit spectroscopy
• Ground-based detection of the near-infrared emission from the dayside of WASP-5b
• Recovering the colour-dependent albedo of exoplanets with high-resolution spectroscopy: from ESPRESSO to the ELT
• Non-Axisymmetric Flows on Hot Jupiters with Oblique Magnetic Fields
• A SEA BASS on the exoplanet HD209458b
• Reassessing Exoplanet Light Curves with a Thermal Model
• Phase Curves of the Kepler-11 Multi-Planet System
• The phase curve of the ultra-hot Jupiter WASP-167b as seen by TESS
• High-resolution transmission spectroscopy of the hot-Saturn HD 149026b
• A New Method for Calibration of Gain Variation in Detector System
• The role of host star variability in the detectability of planetary phase curves
• Reflected light from giant planets in habitable zones: Tapping into the power of the Cross-Correlation Function