  The intrinsic variability due to the magnetic activity of young active stars
is one of the main challenges in detecting and characterising exoplanets. We
present a method able to model the stellar photosphere and its surface
inhomogeneities (starspots) in young/active and fast-rotating stars, based on
the cross-correlation function (CCF) technique, to extract information about
the spot configuration of the star. Within the Global Architecture of Planetary
Systems (GAPS) Project at the Telescopio Nazionale Galileo, we analysed more
than 300 spectra of the young planet-hosting star V1298 Tau provided by HARPS-N
high-resolution spectrograph. By applying the SpotCCF model to the CCFs we
extracted the spot configuration (latitude, longitude and projected filling
factor) of this star, and also provided the new RVs time series of this target.
We find that the features identified in the CCF profiles of V1298 Tau are
modulated by the stellar rotation, supporting our assumption that they are
caused by starspots. The analysis suggests a differential rotation velocity of
the star with lower rotation at higher latitudes. Also, we find that SpotCCF
provides an improvement in RVs extraction with a significantly lower dispersion
with respect to the commonly used pipelines, with consequent mitigation of the
stellar activity contribution modulated with stellar rotation. A detection
sensitivity test, by the direct injection of a planetary signal into the data,
confirmed that the SpotCCF model improves the sensitivity and ability to
recover planetary signals. Our method enables the modelling of the stellar
photosphere, extracting the spot configuration of young/active and rapidly
rotating stars. It also allows for the extraction of optimised RV time series,
thereby enhancing our detection capabilities for new exoplanets and advancing
our understanding of stellar activity.
