2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41448In the framework of perturbative QCD and a model for the production of charmed hadrons the structure function $F^c_2$ is calculated and compared with the experimental data of H1 and ZEUS Collaborations. We show that the spectator mechanism of the $D^*$-meson production independent of a hadronic remnant is valid at $p_T>10$ GeV, only. We find that the evolution of $F^c_2(x,Q^2)$ versus the virtuality $Q^2$ can be neglected in the kinematic region of HERA.21 pages, 9 figuresHigh Energy Physics - Phenomenologytext