This is the 3747th most frequent Turkish word.
yıldızın
"Yıldızın" means "your star" in English.
In this sentence, "yıldızın" shows possessive (genitive case) to indicate that the light belongs to the star.
Gökyüzünde parlayan yıldızın ışığı büyüleyiciydi.
The light of the star shining in the sky was enchanting.
Here, "yıldızın" refers to possessive usage to denote that the performance belongs to the star (the actor).
Bu tiyatroda yıldızın performansı gerçekten etkileyiciydi.
The performance of the star in this theater was truly impressive.
In this example, "yıldızın" is used in the genitive case to specify that the documentary is about the star's life.