The nine grahas of Jyotisha are literally 'seizers' — each takes hold of some part of your life. Surya, the Sun, is the core of soul and self (ātma-kāraka): the thing that makes you you and not someone else. It's the only body in the sky that shines by itself, so it governs everything that exists without depending on anyone: self-respect, vitality, authority, the father.
Mechanically, the Sun is at home in Leo, exalted in Aries and debilitated in Libra, and those three placements say one thing: the Sun needs a place where it can shine and room to be acknowledged. It pairs with the Moon: the Sun is who you are, the Moon is how it feels.
Where you'll recognise it: needing to be taken seriously, strong feelings about authority (father included), being overlooked hurting more than being criticised. Running well, the Sun is the steadiest centre there is: you know who you are, you needn't prove it, you light the people near you. Stuck, it's too bright or too dim — arrogance that can't hear, or the reverse, self-respect in pieces and needing everyone's approval. The Sun's lesson has only ever been one: stand in the place that's yours, no more and no less.
