First PoET Results on Granulation-Driven Radial Velocities from Disk-Resolved Solar Observations

Precise radial velocity (RV) measurements are fundamentally limited by stellar surface processes, with granulation emerging as a key source of short-timescale RV variability. Understanding its impact at the level of individual spectral lines is essential both for solar physics and for the mitigation of stellar noise in exoplanet searches.In this contribution, I will present the first results obtained with the new PoET telescope, focusing on granulation-driven RV signals in disk-resolved solar observations. These measurements represent some of the earliest scientific results from PoET, and the first to specifically address granulation effects using this facility.The analysis is performed with TILARA (Template-Independent Line-by-line Algorithm for Radial velocity Analysis), a line-by-line RV extraction code based on iterative multi-Gaussian fitting of individual absorption lines, avoiding the use of spectral templates. TILARA enables direct control over individual line selection and weighting, making it particularly well suited to explore how different spectral features respond to granulation.I will present a first preliminary classification of spectral lines according to their sensitivity to granulation, identifying lines that are strongly affected and others that appear more stable. These early results provide a proof of concept for PoET’s capabilities and demonstrate how line-resolved RV analysis can be used to link granulation properties to measurable RV signals.This work opens a new observational window on solar granulation and establishes a framework to connect disk-resolved solar measurements with unresolved stellar RV observations, with direct implications for activity mitigation in high-precision exoplanet surveys.