When the nodes join the Sun, it is an interesting situation because the Sun is a masculine planet and whenever the nodes join a planet, it really accentuates the gender of that planet.
Rahu / Ketu and (the Sun)
When either node joins the Sun, you will see a lot of masculine energy (whether it is for a man or a woman). For a man, it will tend to concentrate that masculine energy. It can even make him quite attractive to women. It is going to do it in different ways and that is not the only thing that you will see.
Because the nodes tend to magnify whatever they join, Rahu/Sun will tend to amplify that quality of the Sun which is about, for instance, confidence. The person will seem to have a lot of confidence. You will see wild expression of confidence, sometimes they are overconfident and other times they are insecure. This issue of confidence becomes a big theme in the person’s life when we have Rahu joined the Sun.
The same thing happens with Ketu but Ketu is more of an internal implosive force. Ketu/Sun will also bring a lot of masculine power but it is often like a strong, silent type where the person is stoic. That internal nature of the Sun is very concentrated.
When you have Rahu joined something, it expresses itself a lot because there is a certain amount of immaturity associated with it. So in Rahu/Sun, there is an immature expression of the Sun where they over-express or under-express confidence. These wild swings between over-confidence and under-confidence will be seen with Rahu/Sun.
In Ketu/Sun, there is a lot of perfectionism, intelligence and wisdom around the Sun because this is what Ketu is about. It is about completing the Karma and concentrating that energy. Instead of these erratic displays of confidence, in Ketu/Sun there will be a sort of concentrated power internal but there is still a lack of consistency because the person is trying to really purify the nature of the Sun.