T Tauri star. Artwork of a type of young cool star known as a T Tauri star. This star has not yet entered the hydrogen-burning (main-line) phase of stellar evolution. It is still forming from a stellar nebula and has an associated disc (red cloud surrounding it) from which it gathers mass. It also undergoes extensive mass loss via a strong stellar wind. It rotates rapidly, having strong magnetic fields and many starspots (dark areas).