Average line profiles of Ca II H&K (left) and Ca II IRT (right) for WASP-33b (top) and KELT-9b (bottom). The gray points are original transmission spectra and the black circles are spectra binned every seven points. The red lines are Gaussian fits to the line profiles. The fitted results are presented in Table 4. The blue lines are model spectra calculated assuming isothermal temperatures and tidal locked rotation.