Cross-correlation results of Cr I lines for the six UHJs. For each of the studied planets, we present the following plots. Left: Residuals map for Cr I, where the white tilted line represents the expected velocity of the planet and red horizontal lines show the beginning and the end of the transit, region where we expect the signal from the planet; center map: K_p map for K_p in the range of 0 to 300 km s⁻¹ and the red line represents the theoretical K_p value for the planet. We expect the signal to be coming from a planet at radial velocity of 0 km s⁻¹ and theoretical K_p. Right: S/N plot for expected K_p value, the grey vertical lines represent 0 km s⁻¹ and gray region represents S/N between −3 and 3.