Surveying Ultra-hot Jupiters using Phase Curves with $\textit{Twinkle}$

TL;DR

This paper forecasts the capabilities of the upcoming Twinkle mission to conduct phase curve observations of ultra-hot Jupiters, enabling detailed atmospheric characterization and insights into their chemistry, dynamics, and evolution.

Contribution

It introduces a simulation framework for Twinkle's phase curve survey of UHJs, demonstrating its potential to detect atmospheric features and measure phase offsets across multiple wavelengths.

Findings

Twinkle can detect all phase curve signals in the simulated survey.

Spectroscopic phase curves reveal key molecular features like H2O, CO, and CO2.

The survey will be the first to provide simultaneous optical and infrared phase curves of UHJs.

Abstract

Due to their high equilibrium temperatures ($T_{eq}$ $>$ 2000 K), ultra-hot Jupiters (UHJs) are the best characterized exoplanets to date. However, many questions about their formation, evolution, and atmospheres remain unanswered. Phase curve observations can reveal answers to these questions by constraining multiple atmospheric properties including circulation, albedo, and chemistry. To this end, we simulate and forecast a survey of UHJ atmospheres via phase curve observations with the upcoming $\textit{Twinkle}$ mission. $\textit{Twinkle}$ is a spectroscopic satellite covering 0.5--4.5 micron with a spectral resolving power of R $\sim$ 50--70. Using a physically motivated model, we simulate white-light photometric phase curve observations for 14 UHJs in $\textit{Twinkle's}$ field of regard. We project that $\textit{Twinkle}$ will be able to detect all phase curve signals in our survey. Additionally, we simulate spectroscopic phase curves for the UHJ, WASP-189b. From our simulated spectroscopic phase curves, we generate mock phase-resolved emission spectra. Previously detected UHJ molecules (e.g. H$_2$O, CO and CO$_2$) produce notable features in the resulting spectra, allowing for detailed atmospheric characterization to study the 3D structure of UHJ atmospheric chemistry and dynamics. For planets with hotspot phase offsets, $\textit{Twinkle}$ will be capable of detecting them both in the optical and infrared wavelength ranges. This future survey would represent the first UHJ phase curve survey with simultaneous coverage in optical and infrared wavelengths and will provide new constraints and reveal intriguing trends in these extreme environments.