Bhagavatapurana 3.11.13

3.11.13

graharkṣa-tārā-cakra-sthaḥ paramāṇv-ādinā jagat /
saṃvatsarāvasānena paryety animiṣo vibhuḥ //

13. The powerful deity Surya is the embodiment of Time and he occupies the Kalachakra (the sphere of Time) consisting of the planets, Asvini and other constellations and stars in general and goes round the world embraced by the twelve signs of the zodiac in a period of time beginning with the atomic division of time and ending with the year.