Searching for Molecular Signatures in 14 Transiting Exoplanets with SPIRou

TL;DR

This study conducts a systematic, homogeneous analysis of archival high-resolution spectroscopic data from 14 transiting exoplanets using SPIRou, confirming known atmospheric molecules and tentatively detecting others, advancing ground-based exoplanet atmosphere studies.

Contribution

It introduces a scalable, automated method for analyzing large spectroscopic archives, enabling systematic atmospheric characterization of diverse exoplanets.

Findings

Confirmed H2O and CO in multiple exoplanets

Tentative H2S detections in some planets

Provided upper limits for non-detections

Abstract

High-resolution spectroscopy provides unique constraints on exoplanet atmospheric composition and dynamics. The past decade of ground-based campaigns has accumulated extensive public archives, yet many observations remain unanalysed. We present a homogeneous blind-search analysis of 50 SPIRou transits spanning 14 exoplanets, ranging from super-Earths to ultra-hot Jupiters, combining data from large program and public archived observations. Using automated data reduction and atmospheric retrieval via Nested Sampling validated by Cross Correlation Function analysis, we confirm previous H2O and CO detections in HD 189733 b, WASP-76 b, and WASP-127 b, report tentative H2S detections in HD 189733 b and TOI-1807 b, tentative detection of GJ 3470 b's atmosphere, and provide upper limits for non-detections. This work demonstrates a scalable method for systematic archive analysis, providing a first step toward ground-based support of large space-based atmospheric characterization programs and the study of atmospheric diversity across exoplanet populations from a statistical perspective.