The Sun is the core of identity — vitality, conscious will, and the central self a person is organized around. It describes purpose and the drive to express who you are.
As a transit the Sun illuminates and energizes whatever natal point it contacts for a day or two, bringing it briefly to the foreground of awareness. Fast and recurring, it is a spotlight rather than a turning point.
identity, confidence, recognition, the will to act, and the part of the chart currently asking to be expressed.
Transit Sun conjunct natal Mercury sharpens focus on communication and puts your ideas front and center for a day.