Aruṇa (Aruna) is the son of king Haryaśva (Haryaswa), belonging to Sūryavaṁśa (Suryavamsa; the Solar dynasty). He is the father of Triśanku (Trisanku; whose earlier name was Satyavrata).
However Bhāgavatapurāṇa (Bhagavatapurana) states that Aruṇa was the father of Trivandhana, and Trivandhana was the father of Satyavrata Triśanku.