[..] The first formal compendia of star lists are the Three Stars Each texts appearing from about the twelfth century BC. They represent a tripartite division of the heavens: the northern hemisphere belonged to Enlil, the equator belonged to Anu, and the southern hemisphere belonged to Enki. The boundaries were at 17 degrees North and South, so that the Sun spent exactly three consecutive months in each third. The enumeration of stars in the Three Stars Each catalogues includes 36 stars, three for each month. The determiner glyph for "constellation" or "star" in these lists is MUL (𒀯), originally a pictograph of three stars, as it were a triplet of AN signs; e. g. the Pleiades are referred to as a "star cluster" or "star of stars" in the lists, written as MUL.MUL, or MULMUL (𒀯𒀯).[..]

Further clarification: https://en.m.wikipedia.org/wiki/MUL.APIN

Also: sun is Ut or Utu in the epic of Gilgamesh in early Mesopotamian pantheon and later became Shamash in Sumerian/Babylonian