C) Our Sun will probably undergo at least one nova when it becomes a white dwarf about 5 billion years from now. D) When a star system undergoes a nova, it brightens considerably, but not as much as a star system undergoing a supernova.) Our Sun will probably undergo at least one nova when it becomes a white dwarf about 5 billion years from now. D) When a star system undergoes a nova, it brightens considerably, but not as much as a star system undergoing a supernova.