GRASS: Distinguishing Planet-induced Doppler Signatures from Granulation with a Synthetic Spectra Generator

Owing to recent advances in radial-velocity instrumentation and observation techniques, the detection of Earth-mass planets around Sun-like stars may soon be primarily limited by intrinsic stellar variability. Several processes contribute this variability, including starspots, pulsations, granulation. Although many previous studies have focused on techniques mitigate signals from pulsations other types magnetic activity, granulation noise has date only been partially addressed empirically-motivated strategies magnetohydrodynamic simulations. To address deficit, we present GRanulation And Spectrum Simulator ($\texttt{GRASS}$), a new tool designed create time-series synthetic spectra with granulation-driven variability spatially- temporally-resolved observations solar absorption lines. In work, $\texttt{GRASS}$, detail its methodology, validate model against disk-integrated observations. As first-of-its-kind empirical for spectral due star perfectly known center-of-mass behavior, $\texttt{GRASS}$ is an important testing methods disentangling granular line-shape changes true Doppler shifts.