The Impact of Different Haze Types on the Atmosphere and Observations of Hot Jupiters: 3D Simulations of HD 189733b, HD209458b and WASP-39b

TL;DR

This study uses 3D simulations to explore how different haze types affect the atmospheric structure, circulation, and observable spectra of hot Jupiters HD 189733b, HD 209458b, and WASP-39b, revealing haze-induced asymmetries and their observational signatures.

Contribution

It introduces a comprehensive 3D modeling approach to assess the impact of various haze types on hot Jupiter atmospheres and their observable features, highlighting haze effects on circulation and transmission spectra.

Findings

Haze radiative impact drastically alters thermal structure and circulation.

Superrotating jets influence haze distribution and transit depth.

Morning terminator haze opacity may cause observable asymmetry.

Abstract

We present the results from the simulations of the atmospheres of hot-Jupiters HD189733b, HD209458b and WASP-39b, assuming the presence of three different types of haze. Using a 3D General Circulation Model, the Unified Model, we capture the advection, settling and radiative impact of Titan-like, water-world-like and soot-like haze, with a particle radius of 1.5 nm. We show that the radiative impact of haze leads to drastic changes in the thermal structure and circulation in the atmosphere. We then show that in all our simulations, 1) the superrotating jet largely determines the day-to-night haze distribution, 2) eddies drive the latitudinal haze distribution, and 3) the divergent and eddy component of the wind control the finer structure of the haze distribution. We further show that the stronger the absorption strength of the haze, the stronger the superrotating jet, lesser the difference of the day-to-night haze distribution, and larger the transit depth in the synthetic transmission spectrum. We also demonstrate that the presence of such small hazes could result in a stronger haze opacity over the morning terminator in all three planets. This could lead to an observable terminator asymmetry in WASP-39b, with the morning terminator presenting a larger transit depth than the evening terminator. This work suggests that, although it might not be a typical detection feature for hot-Jupiters, an observed increase in transit depth over the morning terminator across the UV and optical wavelength regime could serve as a strong indicator of the presence of haze.