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Title: 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 we use it to fit published Hubble and Spitzer eclipse data. We infer a near-infrared geometric albedo of 24% ± 1% and a cooler dayside temperature of 1483 ± 10 K. Additionally, we perform light curve inversion on the three published orbital phase curves of WASP-43b and find that each suggests 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 ± 11 K. The cooler dayside and hotter nightside suggest a heat recirculation efficiency of 51% 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 temperaturesmore » 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 light curve be non-negative.« less

Authors:
;  [1]
  1. Department of Physics, McGill University, 3600 rue University, Montréal, QC H3A 2T8 (Canada)
Publication Date:
OSTI Identifier:
22654361
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 849; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ALBEDO; BRIGHTNESS; DIAGRAMS; ECLIPSE; EFFICIENCY; EMISSION; ENERGY BALANCE; HEAT; HEAT EXCHANGERS; HEAT TRANSFER; IRRADIATION; JUPITER PLANET; SATELLITE ATMOSPHERES; SATELLITES; STARS; SURFACES; VISIBLE RADIATION; WATER

Citation Formats

Keating, Dylan, and Cowan, Nicolas B. Revisiting the Energy Budget of WASP-43b: Enhanced Day–Night Heat Transport. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA8B6B.
Keating, Dylan, & Cowan, Nicolas B. Revisiting the Energy Budget of WASP-43b: Enhanced Day–Night Heat Transport. United States. doi:10.3847/2041-8213/AA8B6B.
Keating, Dylan, and Cowan, Nicolas B. Wed . "Revisiting the Energy Budget of WASP-43b: Enhanced Day–Night Heat Transport". United States. doi:10.3847/2041-8213/AA8B6B.
@article{osti_22654361,
title = {Revisiting the Energy Budget of WASP-43b: Enhanced Day–Night Heat Transport},
author = {Keating, Dylan and Cowan, Nicolas B.},
abstractNote = {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 we use it to fit published Hubble and Spitzer eclipse data. We infer a near-infrared geometric albedo of 24% ± 1% and a cooler dayside temperature of 1483 ± 10 K. Additionally, we perform light curve inversion on the three published orbital phase curves of WASP-43b and find that each suggests 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 ± 11 K. The cooler dayside and hotter nightside suggest a heat recirculation efficiency of 51% 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 light curve be non-negative.},
doi = {10.3847/2041-8213/AA8B6B},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 849,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}