All the Pandavas and Kauravas were direct descendents of Surya.
King Kuru, from whom the dynasty got its name is the son of Tapati, daughter of Surya
Through Tapati, the daughter of Surya, Samvarana had a son named Kuru. Since Kuru was learned in the way of dharma, all the subjects instated him as their king. It is after his name that Kurujangala has become so famous in the world.
- 89, Sambhava parva, Mahabharata.
Gandharva chitraratha says to Arjuna
“O Partha! This is the story of the greatly fortunate Tapati of ancient times. She was the daughter of Vivasvat (Surya) and it is after her that you are named Tapatya. O Arjuna! O greatest among those who scorch! On Tapati, King Samvarana had a son named Kuru. Born in that lineage of Tapati, you are known as Tapatya.”
- 163, Chaitraratha parva, Mahabharata.