What is the ruling on a female student kissing her shaykh's hand out of gratitude and veneration for him, especially if he is in the position of her father?

If the scholar is a mahram to the woman, there is no harm in kissing his hands, because it is permissible or even recommended to kiss the hand of a scholar, a righteous person, or a noble person. However, if he is a stranger (not a mahram) to her, it is not permissible for her to touch his hand or kiss it.