A transition between the hot and the ultra-hot Jupiter atmospheres

Abstract

[Abridged] A key hypothesis in the field of exoplanet atmospheres is the trend of atmospheric thermal structure with planetary equilibrium temperature. We explore this trend and report here the first statistical detection of a transition in the near-infrared (NIR) atmospheric emission between hot and ultra-hot Jupiters. We measure this transition using secondary eclipse observations and interpret this phenomenon as changes in atmospheric properties, and more specifically in terms of transition from non-inverted to inverted thermal profiles. We examine a sample of 78 hot Jupiters with secondary eclipse measurements at 3.6 μm and 4.5 μm measured with Spitzer Infrared Array Camera (IRAC). We measure the deviation of the data from the blackbody, which we define as the difference between the observed 4.5 μm eclipse depth and that expected at this wavelength based on the brightness temperature measured at 3.6 μm. We study how the deviation between 3.6 and 4.5 μm changes with theoretical predictions with equilibrium temperature and incoming stellar irradiation. We reveal a clear transition in the observed emission spectra of the hot Jupiter population at 1660 +/- 100 K in the zero albedo, full redistribution equilibrium temperature. We find the hotter exoplanets have even hotter daysides at 4.5 μm compared to 3.6 μm, which manifests as an exponential increase in the emitted power of the planets with stellar insolation. We propose that the measured transition is a result of seeing carbon monoxide in emission due to the formation of temperature inversions in the atmospheres of the hottest planets. These thermal inversions could be caused by the presence of atomic and molecular species with high opacities in the optical and/or the lack of cooling species. We find that the population of hot Jupiters statistically disfavors high C/O planets (C/O>= 0.85).

Accepted 11th May 2020

References in corpus (32)

• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• Detection of Thermal Emission from an Extrasolar Planet
• Line and Mean Opacities for Ultracool Dwarfs and Extrasolar Planets
• Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
• The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b
• Spitzer Secondary Eclipses of the Dense, Modestly-irradiated, Giant Exoplanet HAT-P-20b Using Pixel-Level Decorrelation
• Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands
• An ultrahot gas-giant exoplanet with a stratosphere
• A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• A Universal Scaling for the Energetics of Relativistic Jets From Black Hole Systems
• A spectral survey of an ultra-hot Jupiter: Detection of metals in the transmission spectrum of KELT-9 b
• Methane, Carbon Monoxide, and Ammonia in Brown Dwarfs and Self-Luminous Giant Planets
• Hot Nights on Extrasolar Planets: Mid-IR Phase Variations of Hot Jupiters
• 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
• On the Absorption and Redistribution of Energy in Irradiated Planets
• Neutral Iron Emission Lines From The Day-side Of KELT-9b -- The GAPS Programme With HARPS-N At TNG XX
• Treatment of overlapping gaseous absorption with the correlated-k method in hot Jupiter and brown dwarf atmosphere models
• Atmospheric Characterization of the Hot Jupiter Kepler-13Ab
• Deciphering the Atmospheric Composition of WASP-12b: A Comprehensive Analysis of its Dayside Emission
• Climate of an Ultra hot Jupiter: Spectroscopic phase curve of WASP-18b with HST/WFC3
• Thermal Emission of Exoplanet XO-1b
• WASP-80b has a dayside within the T-dwarf range
• New Avenues for Thermal Inversions in hot Jupiters
• Evidence for H${}_2$ Dissociation and Recombination Heat Transport in the Atmosphere of KELT-9b
• The Very Low Albedo of WASP-12b From Spectral Eclipse Observations with $\text{Hubble}$
• Phase Offsets and the Energy Budgets of Hot Jupiters
• Characterization of the atmosphere of the hot Jupiter HAT-P-32Ab and the M-dwarf companion HAT-P-32B
• Hubble PanCET: An isothermal day-side atmosphere for the bloated gas-giant HAT-P-32Ab
• Colour-magnitude diagrams of transiting Exoplanets - II. A larger sample from photometric distances
• Colour-colour and colour-magnitude diagrams for Hot Jupiters

Cited by in corpus (47)

• A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b
• Hot Jupiters: Origins, Structure, Atmospheres
• Exploring the Effects of Active Magnetic Drag in a GCM of the Ultra-Hot Jupiter WASP-76b
• A unique hot Jupiter spectral sequence with evidence for compositional diversity
• The Roasting Marshmallows Program with IGRINS on Gemini South I: Composition and Climate of the Ultra Hot Jupiter WASP-18 b
• Into the Storm: Diving into the winds of the ultra hot Jupiter WASP-76 b with HARPS and ESPRESSO
• High atmospheric metal enrichment for a Saturn-mass planet
• Grid of Pseudo-2D Chemistry Models for Tidally-Locked Exoplanets. I. The Role of Vertical and Horizontal Mixing
• The GAPS Programme at TNG. XLI. The climate of KELT-9b revealed with a new approach to high spectral resolution phase curves
• New Candidate Extreme T Subdwarfs from the Backyard Worlds: Planet 9 Citizen Science Project
• Evidence for disequilibrium chemistry from vertical mixing in hot Jupiter atmospheres. A comprehensive survey of transiting close-in gas giant exoplanets with warm-Spitzer/IRAC
• Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b
• HST PanCET Program: A Complete Near-UV to Infrared Transmission Spectrum for the Hot Jupiter WASP-79b
• Exoplanet weather and climate regimes with clouds and thermal ionospheres: A model grid study in support of large-scale observational campaigns
• Hot Jupiter Diversity and the Onset of TiO/VO Revealed by a Large Grid of Non-Grey Global Circulation Models
• The PEPSI Exoplanet Transit Survey (PETS). II. A Deep Search for Thermal Inversion Agents in KELT-20 b/MASCARA-2 b with Emission and Transmission Spectroscopy
• The role of clouds on the depletion of methane and water dominance in the transmission spectra of irradiated exoplanets
• Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
• The GAPS Programme at TNG XXXIII. HARPS-N detects multiple atomic species in emission from the dayside of KELT-20b
• The phase curve and the geometric albedo of WASP-43b measured with CHEOPS, TESS and HST WFC3/UVIS
• Modeling the high-resolution emission spectra of clear and cloudy non-transiting hot Jupiters
• A sub-solar metallicity on the ultra-short period planet HIP 65Ab
• A new approach to spectroscopic phase curves: The emission spectrum of WASP-12b observed in quadrature with HST/WFC3
• ACCESS: Confirmation of a Clear Atmosphere for WASP-96b and a Comparison of Light Curve Detrending Techniques
• Measuring Tracers of Planet Formation in the Atmosphere of WASP-77A b: Sub-stellar O/H and C/H ratios, with a stellar C/O ratio and a potentially Super-stellar Ti/H ratio
• Emergent Spectral Fluxes of Hot Jupiters: an Abrupt Rise in Day Side Brightness Temperature Under Strong Irradiation
• Mineral Snowflakes on Exoplanets and Brown Dwarfs: Coagulation and Fragmentation of Cloud Particles with {\sc HyLandS}
• Why is it So Hot in Here? Exploring Population Trends in $\text{Spitzer}$ Thermal Emission Observations of Hot Jupiters using Planet-Specific Self-Consistent Atmospheric Models
• First Comparative Exoplanetology Within a Transiting Multi-planet System: Comparing the atmospheres of V1298 Tau b and c
• Atmospheric Characterization of Hot Jupiter CoRoT-1 b Using the Wide Field Camera 3 on the Hubble Space Telescope
• Constraints on TESS albedos for five hot Jupiters
• Trends in Spitzer Secondary Eclipses
• Refractory and Volatile Species in the UV-to-IR Transmission Spectrum of Ultra-hot Jupiter WASP-178b with HST and JWST
• Thermal Emission from the hot Jupiter WASP-103b in J and Ks Bands
• The Emission Spectrum of the Hot Jupiter WASP-79b from HST/WFC3
• Lessons from Hubble and Spitzer: 1D Self-Consistent Model Grids for 19 Hot Jupiter Emission Spectra
• The role of cloud particle properties on WASP-39b transmission spectrum based on JWST/NIRSpec observations
• Spitzer phase curve observations and circulation models of the inflated ultra-hot Jupiter WASP-76b
• Atmospheric characterization of hot Jupiters using hierarchical models of Spitzer observations
• A Moderate Albedo from Reflecting Aerosols on the Dayside of WASP-80 b Revealed by JWST/NIRISS Eclipse Spectroscopy
• The GAPS Programme at TNG. LXIX.The Dayside of WASP-76b revealed by GIANO-B, HARPS-N and ESPRESSO: Evidence for Three-Dimensional Atmospheric Effects
• Accelerating exoplanet climate modelling: A machine learning approach to complement 3D GCM grid simulations
• Magnetic Drag and 3-D Effects in Theoretical High-Resolution Emission Spectra of Ultrahot Jupiters: the Case of WASP-76b
• On the Utility of Transmission Color Analysis I: Differentiating Super-Earths and Sub-Neptunes
• Thermal emission spectra of the ultra-hot Jupiter WASP-33 b
• Patchy nightside clouds on ultra-hot Jupiters: General Circulation Model simulations with radiatively active cloud tracers
• A new method to correct for host star variability in multi-epoch observations of exoplanet transmission spectra