Seminars at FGG
Single line analysis: a powerful tool to probe exoplanetary atmospheres
Speaker: Mattia Claudio D'Arpa (INAF - Osservatorio Astronomico di Palermo)
Date and time: 2025-06-10 11:00
Transmission spectroscopy is the primary technique to study atomic and molecular species in exoplanetary atmospheres. During transit, starlight filters through the atmosphere, imprinting spectral features that reveal its composition. While cross-correlation with templates effectively detects weak signals by combining many lines, single-line analysis offers insights into vertical distribution, wind patterns, and rotation. I present results from a framework developed for single-line analysis, applied to hot planets like warm-Saturns and hot-Jupiters. For KELT-9 b, using HARPS-N data, we identified 70 lines from seven species, including the first detections of Hϵ, Hζ, Cr II, and Sc II. NLTE models confirmed these detections and highlighted blended regions. The same method applied to TOI-5398 b revealed Hα and He I triplet lines, consistent with predictions from the ATES evaporation model. Finally, for TOI-1518 b, we combined HARPS-N and GIANO-B data, detecting Hα, Na D2, and multiple species through cross-correlation, along with a preliminary detection of average Fe II and Ti II lines.