Shamash was the Akkadian name for the Mesopotamian god of the sun, known to the Sumerians as Utu. He was the twin brother of the goddess Inanna, the Queen of Heaven. His main temples were in the cities of Sippar and Larsa. He is usually depicted as an old man with a long beard. His main symbol was the solar disc, a circle with four points in each of the cardinal directions and four wavy, diagonal lines emanating from the circle between each point. According to Gods, Demons, and Symbols of Ancient Mesopotamia by Jeremy Black and Anthony Green, the Akkadian name for this symbol was shamshatu. It was often represented on a pole as a standard. The symbol is currently a popular icon among people native to Mesopotamia.
The ethnic flag of the Chaldean people features a colored Star of Shamash flanked by 2 parallel blue bands. Though the predominantly Catholic Chaldeans are mostly regarded ethnically and historically as a part of the Assyrian continuity, some claim a Chaldean ethnic identity as a nation of its own. As for the Assyrian people, their ethnic flag also features a Star of Shamash with four triple-coloured, widening, wavy stripes connecting the center to the four corners of the flag. Above the Star is a depiction of the Assyrian pre-Christian god Assur. This flag was adopted in 1971 and is widely used to represent Assyrian identity, both in the homeland and in the diaspora. In a move to promote the position and inclusion of Christian minorities in Iraqi society, the Central Bank of Iraq issued in 2018 a new 1000 Dinar banknote featuring the Star of Shamash.
Some examples featuring the Star of Shamash:
For more examples, please visit this thread on my Twitter.