Ia supernova from a white dwarf, possibly the merger of two white dwarfs. Habitability for hypothetical planets orbiting brown dwarfs has been studied. Gas giants have some of the characteristics of brown dwarfs. Ia supernovae resulting from merging white dwarfs. This may happen in white dwarfs and neutron stars. These become cool helium white dwarfs. This allows astronomers to study these brown dwarfs or exoplanets in more detail. Diamonds may exist in carbon-rich stars, particularly white dwarfs. One interesting field is the study of remnant planetary systems around white dwarfs. These are stars that are closest to the boundary to becoming brown dwarfs (aka. Gobbo stands for Goblin, which is hated by the Dwarfs. Sirius B is one of the most massive white dwarfs known. Ursa Minor has two enigmatic white dwarfs. Molecular hydrogen (H) has been detected in spectra of the atmospheres of some white dwarfs. Brown dwarfs around white dwarfs are quite rare.