High-resolution transmission spectroscopy of warm Jupiters: An ESPRESSO sample with predictions for ANDES

TL;DR

This study uses high-resolution spectroscopy to investigate warm Jupiter atmospheres, reporting non-detections with ESPRESSO and predicting potential future detections with the upcoming ANDES instrument, especially for eccentric orbit planets.

Contribution

It provides the first observational constraints on water in warm Jupiters with ESPRESSO and offers predictions for atmospheric detections with the future ANDES spectrograph.

Findings

Non-detections of water in six warm Jupiters with ESPRESSO.

Simulations predict detectable water and CO in certain eccentric orbit planets with ANDES.

Eccentric orbits may enable access to cooler, more detectable planetary atmospheres.

Abstract

Warm Jupiters are ideal laboratories for testing the limitations of current tools for atmospheric studies. The cross-correlation technique is a commonly used method to investigate the atmospheres of close-in planets, leveraging their large orbital velocities to separate the spectrum of the planet from that of the star. Warm Jupiter atmospheres predominantly consist of molecular species, notably water, methane and carbon monoxide, often accompanied by clouds and hazes muting their atmospheric features. In this study, we investigate the atmospheres of six warm Jupiters K2-139 b, K2-329 b, TOI- 3362 b, WASP-130 b, WASP-106 b, and TOI-677 b to search for water absorption using the ESPRESSO spectrograph, reporting non-detections for all targets. These non-detections are partially attributed to planets having in-transit radial velocity changes that are typically too small to distinguish between the different components (star, planet, Rossiter-McLaughlin effect and telluric contamination), as well as the relatively weak planetary absorption lines as compared to the S/N of the spectra. We simulate observations for the upcoming high-resolution spectrograph ANDES at the Extremely Large Telescope for the two favourable planets on eccentric orbits, TOI-3362b and TOI-677 b, searching for water, carbon monoxide, and methane. We predict a significant detection of water and CO, if ANDES indeed covers the K-band, in the atmospheres of TOI-677 b and a tentative detection of water in the atmosphere of TOI-3362b. This suggests that planets on highly eccentric orbits with favourable orbital configurations present a unique opportunity to access cooler atmospheres.