Final answer:
Helios is the god described in the question. He was a Titan god of heavenly constellations and associated with the start of the Greek year because of his constellation, Aries.
Step-by-step explanation:
The god who is described in the question is Helios. Helios was a Titan god of heavenly constellations and was also known as a Pillar of the south pole. His name means "Ram" and he was associated with the start of the Greek year because his constellation, Aries, represented the beginning of spring.