Revisiting the Energy Budget of WASP-43b: Enhanced day-night heat transport

Abstract

The large day--night temperature contrast of WASP-43b has so far eluded explanation. We revisit the energy budget of this planet by considering the impact of reflected light on dayside measurements, and the physicality of implied nightside temperatures. Previous analyses of the infrared eclipses of WASP-43b have assumed reflected light from the planet is negligible and can be ignored. We develop a phenomenological eclipse model including reflected light, thermal emission, and water absorption, and use it to fit published Hubble and Spitzer eclipse data. We infer a near-infrared geometric albedo of 27$\pm 1\%$ and a cooler dayside temperature of $1527\pm 10$K. Additionally, we perform lightcurve inversion on the three published orbital phase curves of WASP-43b and find that each requires unphysical, negative flux on the nightside. By requiring non-negative brightnesses at all longitudes, we correct the unphysical parts of the maps and obtain a much hotter nightside effective temperature of $1076\pm 11$K. The cooler dayside and hotter nightside suggests a heat recirculation efficiency of $47\%$ for WASP-43b, essentially the same as for HD 209458b, another hot Jupiter with nearly the same temperature. Our analysis therefore reaffirms the trend that planets with lower irradiation temperatures have more efficient day-night heat transport. Moreover, we note that 1) reflected light may be significant for many near-IR eclipse measurements of hot Jupiters, and 2) phase curves should be fit with physically possible longitudinal brightness profiles --- it is insufficient to only require that the disk-integrated lightcurve be non-negative.

Accepted for publication in ApJL. 7 pages, 4 figures

References in corpus (12)

• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
• Multi-Wavelength Constraints on the Day-Night Circulation Patterns of HD 189733b
• The Very Low Albedo of an Extrasolar Planet: MOST Spacebased Photometry of HD 209458
• Inverting Phase Functions to Map Exoplanets
• Spitzer Phase Curve Constraints for WASP-43b at 3.6 and 4.5 microns
• The Atmospheric Circulation of the Hot Jupiter WASP-43b: Comparing Three-Dimensional Models to Spectrophotometric Data
• Hot Nights on Extrasolar Planets: Mid-IR Phase Variations of Hot Jupiters
• Balancing the Energy Budget of Short-Period Giant Planets: Evidence for Reflective Clouds and Optical Absorbers
• Thermal Emission from Transiting Very-Hot Jupiters: Prospects for Ground-based Detection at Optical Wavelengths
• Ks band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope
• The stellar obliquity, planet mass, and very low albedo of Qatar-2 from K2 Photometry

Cited by in corpus (30)

• Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b
• A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve
• The cloudy shape of hot Jupiter thermal phase curves
• Climate of an Ultra hot Jupiter: Spectroscopic phase curve of WASP-18b with HST/WFC3
• 2.5-D retrieval of atmospheric properties from exoplanet phase curves: Application to WASP-43b observations
• Detection of a Westward Hotspot Offset in the Atmosphere of a Hot Gas Giant CoRoT-2b
• Systematic Phase Curve Study of Known Transiting Systems from Year 1 of the TESS Mission
• Phase Offsets and the Energy Budgets of Hot Jupiters
• Low albedos of hot to ultra-hot Jupiters in the optical to near-infrared transition regime
• An independent analysis of the Spitzer/IRAC phase curves of WASP43 b
• $TESS$ Phase Curve of the Hot Jupiter WASP-19b
• Exoplanet atmosphere retrievals in 3D using phase curve data with ARCiS: application to WASP-43b
• Aluminium oxide in the atmosphere of hot Jupiter WASP-43b
• NGTS-10b: The shortest period hot Jupiter yet discovered
• An exploration of model degeneracies with a unified phase curve retrieval analysis: The light and dark sides of WASP-43 b
• Revisiting the Iconic Spitzer Phase Curve of 55 Cancri e: Hotter Dayside, Cooler Nightside and Smaller Phase Offset
• Phase curve pollution of exoplanet transmission spectra
• A survey of exoplanet phase curves with Ariel
• The Dark World: A Tale of WASP-43b in Reflected Light with HST WFC3/UVIS
• Smaller than expected bright-spot offsets in Spitzer phase curves of the hot Jupiter Qatar-1b
• The THOR+HELIOS general circulation model: multi-wavelength radiative transfer with accurate scattering by clouds/hazes
• Estimating dayside effective temperatures of hot Jupiters and associated uncertainties through Gaussian process regression
• Spitzer thermal phase curve of WASP-121 b
• Longitudinally Resolved Spectral Retrieval (ReSpect) of WASP-43b
• Constraints on TESS albedos for five hot Jupiters
• Thermal Phase Curves of XO-3b: an Eccentric Hot Jupiter at the Deuterium Burning Limit
• Physically-motivated basis functions for temperature maps of exoplanets
• Effects of Thermal Emission on the Transmission Spectra of Hot Jupiters
• Probing reflection from aerosols with the near-infrared dayside spectrum of WASP-80b
• A Moderate Albedo from Reflecting Aerosols on the Dayside of WASP-80 b Revealed by JWST/NIRISS Eclipse Spectroscopy