But a two-faced star?
Janus is fairly massive for a white dwarf, with a mass 20% larger than that of our sun compressed into an object with a diameter half that of Earth.
About 97% of all stars are destined to become white dwarfs when they die," Caiazzo said.
Janus may represent a white dwarf in the midst of this transitional blending process, but with the puzzling development of one side being hydrogen while the other side is helium.
Janus is not the only exotic white star known.
Janus, Ilaria Caiazzo, Caiazzo, Will Dunham, Daniel Wallis