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Other non-pro-supernova binaries include binaries that consist of a main sequence star (or giant) and a white dwarf. The binary Sirius AB is probably the most famous example. White dwarfs can also exist as binaries or multiple star systems that only consist of white dwarfs. An example of a resolved triple white dwarf system is WD J1953-1019, discovered with Gaia DR2 data. One interesting field is the study of remnant planetary systems around white dwarfs. While stars are bright and often outshine the exoplanets and brown dwarfs that orbit them, the white dwarfs are faint. This allows astronomers to study these brown dwarfs or exoplanets in more detail. The sub-brown dwarf around the white dwarf WD 0806−661 is one such example.