James Joyce's "Araby": What is the role of Mangan's sister in the story?

The character of Mangan’s sister plays the role of an unreachable goal of the narrator. When first introduced to Mangan’s sister, the narrator is peaking out of the window, checking whether or not she will come outside. The action exhibited by the narrator of distancing himself as well as the audience shows that the character of Mangan’s sister will be an object of desire or an unreachable goal. During an interaction between the two in which the girl asks the narrator if he will be attending Araby, the girl does something that hints at her being an unreachable goal. “While she spoke she turned a silver bracelet round and round her wrist. She could not go, she said, because there would be a retreat that week in her convent.” (22-23)The action of the girl playing with her bracelets shows the hesitancy of her wanting to go with him and the fact that she is a nun makes her even more of an unreachable goal. Mangan’s sister role in the story plays into the fact that the narrator wants to go to the Araby, as well as an object of desire for the narrator, other than that, I see no real significance to her character.