With the exception of rare events such as supernovae and supernova impostors, individual stars have primarily been observed in the Local Group,[36] and especially in the visible part of the Milky Way (as demonstrated by the detailed star catalogues available for the Milky Way galaxy) and its satellites.[37] Individual stars such as Cepheid variables have been observed in the M87[38] and M100 galaxies of the Virgo Cluster,[39] as well as luminous stars in some other relatively nearby galaxies.[40] With the aid of gravitational lensing, a single star (named Icarus) has been observed at 9 billion light-years away.[41][42]