When we refer to Mary as “Star of the Sea,” we recall the fact that, like the stars in the sky, her task – in fact, her very nature – is to reflect the Light. The physical stars in the sky reflect the Sun’s light. Mary reflects the Light of her Son, Jesus Christ.
The Brown Scapular isn't something that Our Lady just came up with out of the blue. It has biblical symbolism that goes back to the Old Testament.