Final answer:
In Greek mythology, the mother of Halcyone by Aeolus was Merope.
Step-by-step explanation:
The Heliade referenced in this question was Merope, who was the mother of Halcyone by Aeolus. Merope is one of the Pleiades, the daughters of the titan Atlas and the oceanid Pleione in Greek mythology. Aeolus, the ruler of the winds, was said to have several wives and children across different sources, and Merope is recognized as one of his spouses in some accounts. This question delves into the intricate family trees of Greek mythology, which include many unions between gods, titans, and mortals and often resulted in the birth of various heroes and significant figures in these ancient stories.