915 Cosette is an S-type asteroid<sup>https://web.archive.org/web/20061201092811/http://www.psi.edu/pds/resource/taxonomy.html</sup> belonging to the Flora family of Main Belt asteroids. Its rotation period is 4.445 hours<sup>https://archive.today/20060614093519/http://www.psi.edu/pds/archive/lc.html</sup>.