Rahu is not actually is planet or a visible body in the sky. It is a shadow planet. Rahu is also called the dragon’s head. The motion of Rahu in kundali is in opposite direction than the other planets.
Rahu makes a person want material pleasures.
There is much debate about exaltation and debilitation signs of rahu and ketu. Rahu is strong in Taurus, Gemini and Aquarius.
Rashis ruled by Rahu: –
Rahu Exaltation Rashi : Taurus
Rahu Debilitation Rashi : Scorpio
Nakshatras ruled by Rahu : Adra, Swati, Shatataraka
Rahu is karaka for : Material pleasures
Friends : Mercury, Venus, Saturn
Enemies: Sun, Moon, Mars
Gemstone: Hessonite (Gomedha)
Numbers ruled by Rahu: 4
Marankarak house for Rahu: 9th house