High-resolution spectroscopy is a cornerstone of exoplanet research, providing crucial insights into planetary atmospheres and orbital dynamics. However, variations in the host star, such as those induced by spots and faculae, introduce stellar "noise" that can mimic or obscure atmospheric signals, complicating both atmospheric characterization and precise spectroscopic measurements. While this issue has been extensively explored in low-resolution studies, its impact on high-resolution transmission spectroscopy remains less understood. 

Addressing these effects is essential for improving the accuracy of spectroscopic studies, including those requiring extreme precision.

In this work, we use the Spot Oscillation and Planet code (SOAP 4.0) to investigate how non-occulted stellar spots affect high-resolution transmission spectra for a hot-Jupiter planet orbiting a Sun like star. We quantify the induced distortions in spectral line depths and asymmetries and explore their impact on atmospheric retrievals. Our results highlight the importance of  accurately modeling stellar contamination to disentangle planetary and stellar signals, aiding in the mitigation of stellar noise in high-resolution spectroscopy. These insights contribute to the refinement of correction techniques, benefiting future instruments such as ANDES at the ELT and supporting the precise characterization of exoplanetary atmospheres.