Explosions from White Dwarf Star RS Oph . ... Every 20 years or so, the red giant star dumps enough hydrogen gas onto its companion white dwarf star to set off a brilliant thermonuclear explosion on the white dwarf 's surface. ... The red giant star is depicted on the right of the above drawing , while the white dwarf is at the center of the bright accretion disk on the left. As the stars orbit each other, a stream of gas moves from the giant star to the white dwarf. ... NASA Official: Jay Norris. ...