White Star

Usually decoration; beside filled stars, an unfilled rating place. Next to a name or heading, the text star works as ornament, much like a bullet or border. In a row of stars, count only the filled ones: each ☆ is a point not awarded.

Why do Japanese messages use ☆?

It can act as a divider or add playful tone. Japanese examples documented in a 2020 discussion place ☆ inside names and titles as a decorative break, and at sentence endings for cheerfulness or cuteness. Some convey exaggerated innocence or a performed persona. Treat that as a possible tone in Japanese writing, not a code for every star you receive.