1. Sun in the 12th House
This is the classic aspect for the absent father. He may not have been there emotionally and/or physically. The father may have been in jail, as was the case for one of my friends. He may not have been able to relate to men, as was the case of someone else I know. He may have been a workaholic, as was the case for another person.
2. Sun Conjunct Chiron
This aspect indicates great pain in the relationship with the father. Remember, the orb proximity( i.e closeness of the planets) is key. An exact aspect will be much more painful than a four degree aspect, for example. Sun conjunct Chiron seems to, severely, squelch the voice of the native. The reason may be that he hears the condemning voice of his father in his head.
3. Neptune Conjunct the Sun
In this case, the father may not have been absent physically and/or emotionally. He may have had an addiction of some sort. Neptune rules addictions.He may have wanted to escape the responsibilities of fatherhood. Neptune rules escape mechanisms
4. Uranus Conjunct the Sun
These natives are, generally, brilliant. However, there may be a price to be paid in terms of general ego stability. To me, the price would not be worth it. I think most Sun conjunct Uranus natives would agree, but we can wait to hear from them. Uranus makes that which it touches both brilliant and erratic.In the case of the Sun/Uranus conjunction, Uranus touches the EGO, which the Sun represents. I think of Howard Hughes. He was brilliant, by anyone’s standard but he became a hermit in his later, fearing to leave his room and having to be fed through a mail slot in the door. I do not know if he had this aspect but he could have. Very sad!
5. Sun Square Moon
In this case, the native may have a very hard time accessing his emotions. He may have one separate compartment for his ego and another separate compartment for his emotions. He may appear like a robot. The father may not have been an emotional person. The native may have learned that it is not acceptable to be an emotional person, as well.